The measured polycyclic aromatic hydrocarbon (PAH) levels in falcon blood sampled at Padre Island were significantly higher after the Deepwater Horizon spill. These findings are consistent with those after an oil tanker sank off the coast of Spain in 2002¹. PAHs have been shown to cause severe biological disruptions and death in various organisms¹. Working with our partners, we intend to continue monitoring blood PAH levels in migrating Peregrine Falcons.

Background

In 2010 we initiated a collaborative effort with The Peregrine Fund and the Center for Environmental Sciences and Engineering at the University of Connecticut (CESE) to assess the scope and impacts of the 2010 BP Deepwater Horizon oil spill (DWH) on Tundra Peregrine Falcons (Falco peregrinus tundrius) migrating through the Gulf of Mexico.  Analyses of blood samples collected from Peregrine Falcons during the 2009-2011 South Padre Island (TX) and Assateague Island (MD) surveys sought to quantify exposure to PAH, toxic components of the DWH oil.  PAH analyses were conducted on selected Padre autumn 2010 and spring 2011 blood samples. Pre-DWH controls (Padre autumn 2009, Assateague autumn 2010) were selected from archived samples and analyzed at CESE.  Comparative analyses of pre and post-DWH PAH levels in peregrines are currently being conducted.

Results and Discussion

In common with all vertebrates, birds have well-developed mixed function oxygenase systems that can rapidly metabolize parent PAHs into hydrophilic products that are more easily excreted, thereby making it difficult to determine the chemical structure of the original compound. Consequently, only minor concentrations of parent compounds are usually detectable in vertebrate tissues^{2, 3} and it has been postulated that directly measuring oil constituents in bird tissues does not accurately reflect exposure to xenobiotic parent compounds⁴. Alternative techniques such as PAH metabolite, bile burden or the induction of cytochrome P450^{4, 5, 6} have been developed. However, these assays normally require freshly killed animals.  We present the analysis of PAHs in Peregrine Falcon blood as a convenient and relatively rapid method with little disturbance to birds for monitoring PAH contamination in their avian food chain. Since blood cells are continuously being produced and have a lifespan of several weeks⁷ the presence of PAHs in blood cells probably indicates a recent incorporation during erythropoiesis.

Blood cells were analyzed to determine and quantify hematological levels of PAHs. A blood sample (~2 mL) was taken from the brachiocephalic vein with a heparinized 23 G needle. Blood was immediately transferred to plastic tubes that were kept in coolers (4° C), and the samples were centrifuged at the end of the day. Plasma and red blood cells were separately drawn off by sterile pipette and transferred into cryovials, which were kept frozen until analysis. The PAHs that were selected for analysis were the 15 PAH priority pollutants listed by the United States Environmental Protection Agency⁸. PAH levels in red blood cells were determined by high-performance liquid chromatography coupled to a wavelength programmable fluorescence detector.

In 2010, five months after the DWH spill, the percentage of Peregrine Falcons sampled on Padre Island that exhibited total polycyclic aromatic hydrocarbon (ΣPAH) blood levels >5 ng/g increased relative to those sampled in 2009. Concentrations of ΣPAH in those falcons more than doubled after the spill; adults were twice as likely to exhibit those contaminant levels as juvenile falcons, but PAH levels among juveniles were much higher. Differences between Pre and Post-DWH oil spill sampled peregrines were significant for three compounds (Fluorene, Fluoranthene and Pyrene). Pre-DWH samples were most often positive for Fluoranthine, while post-DWH samples most often identified Fluorene and Pyrene..

To our knowledge, this is the first field study in which levels of PAHs were measured nondestructively in Peregrine Falcons with the purpose of monitoring oil pollution in the marine environment after a large oil spill. Overall, our study demonstrates the use of peregrine blood as a monitoring tool for oil exposure. The technique has successfully tracked temporal changes consistent with the massive oil pollution pulse that resulted from the DWH oil spill of 2010. Peregrine Falcons sampled after the oil spill were more likely to exhibit significant PAH contamination and exhibited double the concentrations of those sampled before. Field experiments done on yellow-legged gulls (Larus michahellis) in Europe after the Prestige oil spill of 2002 strongly suggested that the profile of PAHs in the blood of gulls was influenced by the composition of recently ingested oil, and that measures of PAHs in the blood of gulls are sensitive to the ingestion of small quantities of oil. PAHs are constituents of oil that, upon ingestion, are rapidly metabolized, thereby making it difficult to determine the chemical structure of the original compound. For this reason, it has been postulated that low concentrations of parent PAHs should be expected in vertebrate tissues^{2, 3}. Nonetheless, we found higher concentrations of parent PAHs in the blood cells of peregrines after the DWH oil spill relative to those sampled prior to the spill.

Acute toxicity is expected when birds exposed to the spill ingest oil by preening⁹. However, contaminated prey items are also a potential source of contamination, and continued incorporation of oil products through trophic processes has been documented for seabird species after a large oil spill⁵. The life history characteristics of tundra peregrines exposes them to remnant oil because they frequently occur and feed in coastal and nearshore environments, which are the same areas that received much of the oil spilled in the DWH disaster. Adult yellow-legged gulls in Northwestern Spain are sedentary and feed extensively on benthic and intertidal marine organisms¹⁰. Sub-lethal effects derived from continued oil exposure have been recently documented there for this species¹¹. In the oiled colonies, most of the PAH profiles in gull blood were dominated by Naphthalene (22-38%), indicating a petrogenic (i.e., derived from petroleum) source¹². Although after the 2002 spill the composition of the Prestige oil was probably altered by weathering¹³, Naphthalene was also the dominant parent compound found in subsurface waters¹⁴ and intertidal sediments¹⁵ from oiled areas immediately after the spill. In contrast, gulls from unoiled colonies showed low Naphthalene percentages (6-12%), and profiles were dominated by PAHs with a large number of benzene rings (g4 rings), indicative of a pyrogenic (i.e., not derived from petroleum) source of contamination. In other studies, Naphatalene and tricyclic PAHs also dominated samples from seabird species, including gulls, affected by petrogenic contamination^{6, 16}.The differences in PAH profiles between the gull blood and the Prestige crude oil can be due to oil alterations by weathering, changes in PAH composition in the prey tissues, or specific metabolization of PAH compounds by gulls. There is no information about PAH levels in the blood of yellow-legged gulls before the Prestige spill to complete the classic before-after-control-impact approach¹⁷.

Similar results to the study of PAH contaminants in yellow-legged gulls exposed to the Prestige oil spill in Spain were found for Peregrine Falcons sampled along the Texas gulf coast after the DWH oil spill of 2010.  The striking difference between these two studies is that we had archived pre-DWH oil spill peregrine blood samples for PAH analysis. These were used to compare and contrast the change in PAH frequency and type in the birds after the disaster.  Using a reporting threshold of 5 ng/g we analyzed samples collected at Assateague Island (MD) in fall 2010 and Padre Island in fall 2009; none of those subjects had yet been exposed to DWH contaminants. Only one of 25 Assateague 2010 samples met the reporting limit (4%, average ΣPAH 5.4 ng/g). At Padre Island in 2009 five of 27 (18.6%, average ΣPAH of 7.3 ng/g) met the criteria.   In 2010 after the DWH spill 17 of 71 peregrines exhibited PAH levels above 5 ng/g (23.9%, average ΣPAH 15.6 ng/g).

Not only were the concentrations of ΣPAHs more than doubled between the pre and post-exposed peregrines, but the nature of the PAH contaminants changed significantly.  Both pre-DWH sample sets were predominantly found to contain Fluoranthene as the main PAH contaminant.  As stated in the literature this PAH is derived from a pyrogenic source.  In 2010 there was a major shift in the types of PAH contamination to Fluorine and Pyrene. The cited studies from the Prestige spill determined that increasing concentrations of Fluorene and Pyrene were indicative of recent exposure to oil. Juvenile peregrines were contaminated with these petrogenic compounds at less than half the rate of adults (9 of 50, or 18% vs. 8 of 21, or 38%), but those affected had much higher ΣPAH levels (20.38 ng/g vs. 7.08 ng/g). Our satellite tracking studies show that adult tundra peregrines on migration are likely to fly direct routes between breeding and wintering grounds. Upon arrival at the Gulf coast adult southbound migrants do not hesitate to cross the Gulf of Mexico, having little if any lateral movement along this coast during migration. Juvenile tundra peregrines are known to engage in more exploratory migration behavior than adults. Some could arrive on the Gulf Coast to the east of Texas (close to or within the oil spill region), and rather than continue directly over water follow the coastline west through Texas. Such falcons at Padre would be in the minority of juvenile birds, but they could have higher levels of petrogenic PAHs because of consuming more directly contaminated prey as they moved along the coast from east to west. This interpretation of results by age class may reflect a route of contamination consistent with the geographic distribution of the DWH oil spill in the Gulf of Mexico.

No SPI spring 2011 (n=33) falcon ΣPAH burdens registered above 5 ng/g.  It is noteworthy that contaminant levels and rate of exposure in these northward migrants were considerably below those of the autumn pre-spill southward migrants; this warrants further investigation and interpretation.

Results from this study demonstrate that there was an increased incidence of PAH contamination in Peregrine Falcons sampled along the Texas Gulf coast before and after the DWH oil spill, as well as a significant shift in PAH composition. In 2010 the source of increased PAH contamination for peregrines was crude oil, which was not present the year prior to the spill.

Literature Cited

¹Zuberogoitia, I.,  J. A. Martinez, A. Iraeta, A. Azkona, J. Zabala, B. Jimenez, R. Merino,

G. Gomez. 2006. Short-term effects of the Prestige oil spill on the peregrine falcon (Falco peregrinus) Mar. Pollut. Bull. 52 (2006) 1176–1181.

²Ariese, F., S.J. Kok, M. Verkaik, C. Gooijer, N.H. Velthorst, J.W. Hofstraat. 1993. Synchronous fluorescence spectrometry of fish bile: A rapid screening method for the biomonitoring of PAH exposure. Aquat. Toxicol. 26, 273–286.

³Di Giulio, W.H. Benson, B.M. Sanders, P.A. van Veld. 1995. Biochemical mechanisms: metabolism, adaptation and toxicity. In Fundamentals of Aquatic Toxicology; Rand, G. M., Ed.; Taylor and Francis: Washington, pp 523–561.

⁴Trust, K.A., D. Esler, B.R. Wooding, J.J. Stegeman. 2000. Cytochrome P450 1A induction in sea ducks inhabiting nearshore areas of Prince William Sound, AK. Mar. Pollut. Bull. 40, 397-403.

⁵Esler, D., T.D. Bowman, K.A. Trust, B.E. Ballachey, T.A. Dean, S.C. Jewett, C.E. O’Clair. 2002. Harlequin duck population recovery following the “Exxon Valdez” oil spill: Progress, process and constraints. Mar. Ecol.: Prog. Ser. 241, 271–286.

⁶Troisi, G.M., S. Bexton, I. Robinson. 2006. Polyaromatic hydrocarbon and PAH metabolite burdens in oiled common guillemots (Uria aalge) stranded on the east coast of England (2001–2002). Environ. Sci. Technol. 40, 7938–7943.

⁷Clark, M.R. 1988. Senescence of red blood cells: progress and problems. Physiol. Rev. 68, 503–554.

⁸Keith, L.H., W.A. Telliard. 1979. Priority pollutants 1:  A perspective view. Environ. Sci. Technol. 13, 416–423.

⁹Briggs, K.T., S.H. Yoshida, M.E. Gershwin. 1996. The influence of petrochemicals and stress on the immune system of seabirds. Regul. Toxicol. Pharmacol. 23, 145–155.

¹⁰Munilla, I. 1997. Henslow’s swimming crab (Polybius henslowii) as an important food for yellow-legged gulls (Larus cachinnans) in NW Spain. ICES J. Mar. Sci. 54, 631–634.

¹¹Alonso-Alvarez, C., I. Munilla, M.  López-Alonso, A. Velando. 2007. Sublethal toxicity of the Prestige oil spill on yellow-legged gulls. Environ. Int. 33, 773–781.

¹²Page, D.S., P.D. Boehm, G.S. Douglas, A.E. Bence, W.A. Burns, P.J. Mankiewicz. 1999. Pyrogenic polycyclic aromatic hydrocarbons in sediments record past human activity: a case study in Prince William Sound, AK. Mar. Pollut. Bull. 38, 247–260.

¹³Fernández-Varela, R., M.P. Gómez-Carracedo, P. Fresco-Rivera, J.M. Andrade, S. Muniategui, D. Prada. 2006. Monitoring photooxidation of the Prestige’s oil spill by attenuated total reflectance infrared spectroscopy. Talanta 69, 409–417.

¹⁴Gonzalez, J.J., L. Vinas, M.A. Franco, J. Fumega, J.A. Soriano, G. Grueiro, S. Muniategui, P. Lopez-Mahia, D. Prada, J.M. Bayona, R. Alzaga, J. Albaiges. 2006. Spatial and temporal distribution of dissolved/dispersed aromatic hydrocarbons in seawater in the area affected by the Prestige oil spill. Mar. Pollut. Bull. 53, 250–259.

¹⁵Rodríguez, J.G., M. Incera, R. de la Huz, J. López, M. Lastra. 2007. Polycyclic aromatic hydrocarbons (PAHs), organic matter quality and meiofauna in Galician sandy beaches, 6 months after the Prestige oil-spill. Mar. Pollut. Bull. 54, 1046–1052.

¹⁶Kayall, S., D.W. Connell. 1995. Polycyclic aromatic hydrocarbons in biota from the Brisbane River Estuary, Australia. Estuarine, Coastal Shelf Sci. 40, 475–493.

¹⁷Osenberg, C.W., R.J. Schmitt, S.J. Holbrook, K.E. Abusaba, A.R. Flegal. 1994. Detection of environmental impacts: natural variability, effect of size, and power analysis. Ecol. Appl. 4, 16–30.

Earthspan principals conduct long-term studies on migrating peregrines at Assateague Island, MD/VA (autumn since 1970) and Padre Island, TX (autumn and spring since autumn 1977). We have expended more than 49,000 man-hours of survey time in observing over 60,000 peregrines and capturing nearly 14,000. The tundra Peregrine has made a significant recovery and has been removed from the list of endangered species, yet continued monitoring of populations is imperative. Because of the continuity and standard method for data collection these surveys have become an essential tool in that effort.  Our database at Assateague includes sightings of every other raptor we have observed on the Island since 1970. Nearly 90% of all observations there have been recorded by three experienced individuals, who have also conducted springtime studies at Padre Island. At Padre a more diverse cast of highly qualified individuals has participated .

Our work in these studies with satellite-received telemetry allows us to continue elucidating previously undescribed aspects of the tundra Peregrine’s wintering biology and continental migration and to identify critical habitats. Given available technologies, Assateague and Padre remain ideal laboratories in which to study and address present and future issues of concern to Peregrines, other Neotropical migrants, and humans. In recent years we have studied emerging infectious pathogens such as West Nile Virus and Avian Influenza in partnership with U.S. Government entities, and currently address contaminants through studies related to the 2010 Gulf oil spill.

In 2008 our database allowed us to provide an Expert Declaration on the Draft Environmental Assessment and Management Plan for Take of Migrant Peregrine Falcons in the United States for Use in Falconry. Among other points, we concluded that the standardized average number of migrating Peregrines we observed at Assateague over the preceding 29 years was essentially the same as that seen more than six decades ago (1939-1944), before DDT had serious adverse effects on the reproductive potential of the Peregrine in North America. Our work at Assateague and Padre Islands represents the bulk of tundra Peregrine Falcons banded within the continental United States since the establishment of the Bird Banding Laboratory by the Department of the Interior.  Furthermore, our overall database constitutes the most significant and longest continuous monitoring study on this falcon in the Americas. Long-term studies such as ours are essential to monitoring the stability of wildlife populations, particularly in light of rapid changes that may occur due to contaminants, infectious diseases, habitat loss, climate change and other factors. By the long-term and standardized nature of our studies, we have established levels of observation in stable populations that will quickly raise future concerns if not achieved over a several year period.

In 2011 at Assateague, our 42nd annual study was conducted on the northern (MD) portion of the island. Observations and captures by unit effort were the 6th highest and 9th highest respectively for this long-term study. Between 27 September and 17 October the survey team expended 212 man-hours in the field, recording 325 sightings of Peregrines and capturing 77 different individuals. Two of the falcons captured were previously banded. The 325 sightings included 115 observations and seven recaptures of individuals previously captured during the survey. We also obtained 77 blood samples for collaborative studies. Please see our full report for details on the study.2011 Assateague Report

During the 2011 Padre spring survey period from 8-26 April, we conducted 178 survey hours in the field, recording 289 sightings and capturing 33 individual peregrines.  Of those captured, 8 (24.24 %) were previously banded Padre Returns and 25 (75.76 %) were first banded during the survey.

In autumn 2011 at Padre, we surveyed the wind-tidal flats from 29 September to 24 October and the beachfront from 10-14 October.  During this period we expended 371 survey hours in the field, recording 916 peregrine falcon observations and capturing 202 individuals.  Of those captured 3 (1.49 %) were previously banded and 199 (98.51 %) were first banded this season.  Previously banded captures included one foreign falcon banded as a nestling on Baffin Island, Nunavut and 2 Padre Returns.  Please see our full report for details on the study.2011 Padre Report

White-faced ibis with PTT package

Earthspan principals led a cooperative study to identify the source(s) of DDT-related contamination still plaguing a northern Nevada population of white-faced ibis many years after use of the pesticide was banned in the United States.

The white-faced ibis (Plegadis chihi) is a long-legged wading bird that feeds primarily on invertebrates in wetlands and irrigated croplands. It is a highly social colonial nester and often forages in large aggregations. Due to restricted nesting habitat and potential vulnerability to pesticides, the species is listed by the U.S. Fish and Wildlife Service as a migratory non-game bird of management concern.

Dr. Charles Henny (U.S. Geological Survey; USGS) documented continued troubling levels of DDE (the principal metabolite of the organochlorine pesticide DDT) in a large segment of the white-faced ibis population nesting at Carson Lake in western Nevada. Of twenty eggs collected in 1996, 45% contained >4 ppm DDE, and eggshells averaged 18.3% thinner than normal. This represented no improvement from DDE levels documented in 1985-86, which is contrary to patterns shown for most other avian species in the USA. Analyses of upper digestive tract contents in 18 Carson Lake ibis revealed no organochlorine insecticides; the conclusion was that contamination is not occurring on the Nevada breeding grounds. Identification of contaminant sources was highly desirable because it is likely that different regional cohorts of ibis and other wildlife species are frequenting those same areas.

We captured and blood sampled ibis, then tracked them to wintering locales via satellite-received telemetry. We visited wintering sites to collect earthworms, and analyzed them and the original ibis blood samples for DDE. Birds with highest contamination wintered in the Mexicali Valley of Baja Norte, Mexico, and highest DDE levels were also found in earthworms collected at those corresponding wintering areas. Our findings were published in 2010.Yates etal WFIB DDE 2010 Ecotoxicology

The broad-winged hawk is a neotropical migrant that breeds in eastern and central North American forests and winters primarily from Southern Mexico south through Central America to northern South America (Bolivia and Northern Brazil), with small numbers wintering in southern Florida. Its population status is of concern due to the decline in numbers of birds encountered at some migration observation points since the 1970’s and in some areas of its breeding range in the Eastern United States. Information is available on the natural history of the broad-winged hawk in North America, but little is known of its wintering ecology. Within the continental United States, breeding numbers appear to be stable in some areas but decreasing in others. The Puerto Rican population is classified as Endangered, and these declines are attributed to habitat alterations. Similarly, in the Eastern United States, some areas have reported declines in BWHA associated with human development and alteration of woodlands.

Broad-winged hawk integrated radio tracking

Approach/Objectives
Earthspan’s broad-winged hawk research focused on identifying critical habitat during the breeding season, along migration pathways, and during the boreal winter period. The approach integrated radio tracking via satellite, field monitoring, remote sensing, and a geographical information system (GIS) to identify locations and important landscape and nest site features used by the species. This study filled gaps in knowledge concerning aspects of broad-winged hawk migration and wintering biology and provided data critical for the development of a management plan for broad-winged hawks on federal, state, and private lands throughout its annual range.

Broad-winged hawk

Results
Because broad-winged hawks tend to travel in large flocks that are easily identified on NEXRAD radar imagery, Earthspan and the Clemson University Radar Ornithology Laboratory are attempting – for the first time ever – to correlate migration data of individual BWHAs with flock activity. Results from this study will be useful in the development of an effective resource management strategy for this species that can be applied throughout the Americas. Additionally, information collected about land use practices and environmental contaminant uses will be relevant to the conservation of a variety of other wildlife species.

Earthspan tracked (via satellite) broad-winged hawks from North America to their wintering areas and described important land cover types at the hawks’ destinations (both breeding and wintering). Our research provided information on the extent to which North American nesting populations associate with natural and modified habitats across the non-breeding range. Additionally, information may be acquired to describe their exposure to habitat alteration and environmental contaminants in their wintering areas. The breeding habitat, migratory pathways, and wintering range of broad-winged hawks are also shared by a number of other neotropical migrant species, including several that are species of major conservation concern. This project will set the standard for other research projects to study the movements, migration, and wintering habitats of other neotropical migratory species.

Resulsts from this project were published in The Wilson Quarterly.

Broa-winged hawk tracking map

Ten (7 adult females, 2 second year females, and 1 adult male) peregrine falcons were caught on the Gulf Coast of Mexico in January 1997, 23 (16 adult females, 6 second year females and 1 male) in February 1998. Twelve individual falcons were fitted with satellite received transmitters (PTTs). Six female falcons were fitted with PTTs in 1997 and 8 (7 females and 1 male) were fitted in 1998. Two of the falcons that were fitted with PTTs in 1997 were recaptured and fitted with PTTs in 1998. The movements of these birds were monitored. The movements of 14 peregrines were recorded throughout the wintering period. Using data from both years, median areas for minimum convex polygons at 50% and 90% levels were 1173 and 8311 ha., respectively.

On average birds left wintering ground in the first week of May. Departure dates were similar in both years. Thirteen birds were followed through the spring migration period. One bird that was tagged in both years showed fidelity to its summer (breeding) grounds. Birds summered across northern Canada from Franklin River in the west and to the western coast of Greenland in the east.

PTT data and capture locations of birds caught in more than one year indicate that peregrines use the same area of beach for wintering year after year, and the wintering ranges of those birds tracked in more than one year showed a high degree of overlap.

An area of apparent high density of wintering peregrines was identified near Matamoros.

In 1998, two aerial and one ground-based shorebird counts were made in the lower Laguna Madre. Aerial counts were made in February and April and were of 8,981 and 7,345 individuals, respectively. These were primarily ‘small shorebirds’ that could not be identified to the species level. Ground-based counts were of 14,043 individuals, primarily western and least sandpipers.

Many dead sea turtles were seen on the beach during the survey.

Earthspan provided set-up and training in Geographical Information Systems (GIS) and database management. The aim was to provide Ara with an ability to display and undertake preliminary analyses.

Introduction
A feature of peregrine falcons in many parts of the world is their migratory behavior. Some spend more time in the wintering areas than they do on the breeding grounds. Many that winter along the coast of the Gulf of Mexico breed in arctic regions of North America and Greenland. Contaminants such as organchlorines and polychlorinated biphenyls (PCB’s), can concentrate in peregrine falcons. Along with other products primarily associated with agricultural applications, these contaminants caused population declines in peregrines and a variety of other species through direct mortality and decreased productivity due to eggshell thinning. While the use of the most persistent and lethal organochlorine pesticides has decreased or been curtailed (particularly in developed countries), and tundra peregrine populations have responded favorably, toxins are still present in the environment and found in most peregrines sampled along the coast of the Gulf of Mexico (Henny, et al., 1996). Because the breeding areas generally do not suffer from pollution associated with agriculture, it is likely that the falcons are contaminated primarily either on migration or on their wintering areas. For these reasons, it is as important to understand their ecology while wintering as during the breeding and migration periods. In the case of the study area, there has been the recurring threat that an intracoastal waterway might be built between Brownsville and Tampico.

We present data from peregrine falcons fitted with satellite-based telemetry technology. The data record the movement of the birds during much of their wintering time in 1996/97 and 1997/98. They also detail the timing of migration, and the migratory path for some birds. Data suggest likely breeding areas of these birds. This document summarizes the work on peregrine falcons, and consolidates information from monthly and quarterly reports, Nov 1996-July 1998.

Study Area, Materials, and Methods

Survey, capture, instrumentation and monitoring of falcons
Our study occurred on the Mexican Gulf coast between 23o00’and 24o00’ N latitudes in the state of Tamaulipas, centered on the towns of La Pesca and Tepejuahe. Some capture and survey effort was put into the beach area near Matamoros. This area was chosen for the relative ease of access to the beach and location in an area where an Intracoastal Waterway is being proposed.

The portion of coast within the study area is characterized barrier islands that separate the Laguna Madre from the

Gulf of Mexico vary in width from about 100 m up to 2-km. At high tide, the sandy beach is about 5-20 m in width. The western side of the islands are covered in vegetation including grasses (e.g. seacoast bluestem, Schizachyrium scoparium littoralis) and small shrubs (e.g partridge pea, Cassia fasiculata). The Laguna Madre is cut in a N-S direction by a channel, which remains filled with water throughout the year. The mud flats on either side of the channel are sometimes dry, but are sometimes covered by shallow water. Weather conditions play a role in the extent to which the mud flats are flooded. Local people indicate that the laguna is flooded mostly in the winter. The mainland in our study area has been largely converted to ranch use. Forests that exist are either small relicts of the original vegetation or are secondary growth.

Falcons were trapped using noose-harnessed pigeons under permits issued to Fundación Ara by the Mexican government. T. Maechtle provided USFWS bands listed under his permit. Measurements were taken for all captured birds. Capture locations were recorded using a hand-held GPS reciever. Once trapped, peregrines were hooded, aged, sexed and measured. In 1997 blood was drawn for future contaminant and DNA testing; samples in 1998 were for DNA testing only. All blood samples were archived with Fundación Ara. Some falcons were fitted with satellite-received transmitters (PTT’s), banded and released. Duty cycles for the 30 gram PTTs (for females) were set at 10 hrs on, 22 hrs off for 23 cycles, then 10 hrs on 46 hrs off for 26 cycles, then 10 hrs on 166 hrs off for 38 cycles, then shut down. This schedule allowed for the collection of as much data as possible on the wintering grounds, and the power to follow the migration (north and south) and identify summering areas. The 20-gram tags (for males) were set to maximize wintering-ground data collection, and were to run for a total of 500 hrs. In the days immediately following capture, many falcons were re-sighted, and transmitters appeared to be well tolerated.

Data on falcon locations were collected by the ARGOS system. Data were downloaded by Earthspan and sent ot Fundación Ara at least once per week. Location estimates collected by ARGOS are categorized according to likely accuracy (Z,B,A, 0,1,2,3 in ascending order of accuracy). Location classes 1, 2 and 3 mean that 68% of location estimates would lie within a radius of 1 km, 350 m and 150m respectively. We used only location classes 1-3 for our analyses.

Location estimates were displayed within the ArcView GIS (ESRI, Redlands, Ca.) environment, and analyses of the areas covered by the falcons was done using RANGES V (ITE, Dorset, U.K.) software. We described areas used by peregrines during the winter by minimum polygon area analysis.

Shorebird surveys
In 1997, a pilot study of prey assessments using point counts of the laguna and transects along the beach revealed that these methods would not be useful in counting shorebirds in the study area. In 1998, two surveys were conducted by aircraft, and was supplemented by a ground-based count. The same team that performed aerial surveys conducted the ground survey. A more detailed description of shorebird survey methods used in 1998 can be found in quarterly reports of April and July 1998.

Results

Survey and capture of falcons
From 11-24 January 1997 and 17 February – 11 March 1998 fieldwork aimed at the capture and fitting of PTTs to wintering peregrine falcons was undertaken. Surveys were conducted along the beach connecting Matamoros, La Pesca, Tepejuahe, and Tampico. Locations of falcons sighted by the falcon capture team and by the shorebird survey team while conducting ground based shorebird counts are summarized in Appendix 1, Tables 1 and 2. Locations are mapped in Appendix 2 Map 1. A maximum of 17 falcons were seen but not captured in 1997. In 1998 a maximum of 31 were seen and not captured. The shorebird survey team observed a maximum of 15 peregrine falcons in the winter of 1997/98.

Over the two years of the study 33 peregrine falcons were captured, only two were males. Table 2 summarizes these captures; Appendix 2, Map 1 maps the capture locations. This sex bias in capture was indicative of the ratio of male and female falcons seen on the beach. Throughout the period of fieldwork, only 4-5 male peregrine falcons sere seenIn 1997, ten adult peregrine falcons were captured (1 male and 9 females). In 1998, 22 wintering peregrines (1 male and 21 females) were captured, and one was recaptured.

Fourteen PTTs were fitted to peregrines, (6 females in 1997, and 1 male and 7 females in 1998). Three falcons captured in 1998 had been caught in previous years (two were tagged with PTTs in 1997, and one had been caught in 1996). All three of these were fitted with PTTs in 1998. Appendix 2, Map 1 shows the location of peregrine sighted and captured. Locations of capture for birds trapped in both years of the study were found close to one another.

Wintering areas – location, size, and composition
Appendix 2, Maps 2 and 3 show the scatter of location estimates received for peregrine falcons marked in 1997 and 1998, respectively. Appendix 2, Maps 4 and 5 show the convex polygons that describe the ranging of wintering peregrines at the 90% and 50% levels in 1997 and 1998, respectively. Table 3 shows the areas covered by these polygons. Most peregrines stayed throughout the winter period on the stretch of beach where they were captured. Some birds (14505, 12845, 12850, and 12851) did shift their movement patterns so that more than one area of activity concentration were evident (See Maps 2 and 3.). In most cases these movements were along a north-south axis and represent no change in the general habitat used by the peregrines (i.e. beach and laguna). Falcon 12850 did move from the beach where it was captured to an area along a creek.

When the ranges of birds that shifted their areas of activity concentration were removed, the size of the ranges in 1997 were larger than those in 1998 at both the 50% (P= 0.003, F test) and 90% level ( P= 0.005, F-test). For both birds that were marked in both years ranges at the 50% and 90% level were larger in 1997 than in 1998 (Table 4). Appendix 2, Map 5 shows the location estimates of peregrines that were tagged in both years.

Padre Report-2010-FINAL

The Swainson’s Hawk

Approach/Objectives
Thirty Swainson’s hawks were captured and tagged with satellite-received transmitters during July, August, and September 1996, in eight locales within the western United States and Canada: California (one), Colorado (three), Idaho (six), Minnesota (two), Oregon (six), Utah (three), Arizona (two), Saskatchewan or Alberta, Canada (seven). Birds typically departed from nesting areas in mid to late September and arrived in Argentina beginning in the second week of November. By late November, 25 of the 30 Swainson’s hawks had crossed the Argentinean border and by mid-December had settled into the Pampas region of central Argentina. In January of 1996, scientists visited different areas indicated by the satellite derived location data. They counted over 4,000 dead SWHA, killed as an apparent side effect of pesticide applications to Argentinean croplands, and these scientists believed the actual mortality numbers might have exceeded 20,000. This loss represented a serious threat to the survival of the species. Biologists in Argentina gathered blood samples for chemical analyses and attempted to gather behavioral data to relate behavior and ecology to land uses, environmental contaminants, and other threats

The Swainson’s Hawk

Results/Conclusion
We learned that the catastrophic population decline resulted from the use of a toxic organophosphate pesticide, recently brought into use on the Argentinean Pampas where these hawks winter in communal roosts. Through the use of remote tracking and monitoring technology, this environmental problem was identified and, within 18 months, remedied through collaborative government and private sector management and education. Keeping this raptor off the endangered species list saved millions of federal dollars by avoiding costly large-scale research and recovery programs and related habitat management activities in North America. This application of wildlife tracking via satellite is a perfect demonstration of the unique advantage this technology can provide in the study of a wide-ranging species

Swainson's Hhawk migration map

Introduction
Mexico’s national bird, the golden eagle (Aquila chrysaetos), is classified as “in danger” in Article 9 of the Federal Hunting Law (SEDUE 1984) and Ramos (1986) classifies the population as declining, primarily due to decreases in habitat quality. Environmental pollution (particularly pesticides), direct persecution, and illegal trade are all thought to play a part in the decline (Ramos 1986). Although some information exists about the natural history of golden eagles in the southwestern United States of America, very little is published about this species in the most southern reaches of its North American distribution. The long-term survival of the Mexican golden eagle population depends upon understanding its status, its biology, and details of its prey and habitat. A lack of data undermines conservation efforts for the golden eagle, as well as for plants and animals associated with it. For this reason, basic research must be conducted on the golden eagle in Mexico. New information will promote the conservation of this species, which is important both ecologically and culturally to the Mexican people, and the conservation of other, less high-profile species associated with the eagle and its habitat. This research also will add to the knowledge of this cosmopolitan, but difficult to study eagle.

Throughout their range, golden eagles typically prefer open habitats, especially in mountains / hills. If successful, they raise 1 brood per year. They especially prefer jackrabbits-sized prey, but will feed on other prey (even carrion) when food items of this size are scarce. They typically form long-term pair bonds that are based upon long-term occupancy of a single nesting territory by both pair members. In most of the western US, territories are occupied year-round.

A study of the golden eagle in Mexico

The purpose of this study was to increase understanding of the ecology of golden eagles in Mexico, so that an effective management plan could be developed to conserve them. The aims of the project focussed on describing movements of breeding golden eagles, and assessing the habitat upon which they depend. Movements of both breeding birds and non-breeding eagles were to be monitored throughout the year using radio telemetry via satellite. This information was of interest because little is known about the space/habitat requirements of breeding birds in Mexico, or of the requirements of non-breeding and wintering birds. Conventional telemetry was to provide localized data on behavior, diet, and habitat use. Also, it was a means of determining the fate of eagles whose PTTs had ceased operating properly.

Methods were chosen to compliment one another, and to draw on our own experience, the experience of other experts in the field, and published information. Some methods were chosen because they allowed us to better understand the ecology of Mexican eagles by being comparable to studies elsewhere in the world. Our methods utilized new technologies, which should have enabled us to collect unique data on golden eagle ecology.

It was understood from the beginning that because eagles are long-lived, the mileposts in their lifetime reproductive strategy can only be achieved after a number of years. For this reason, studies of eagles are better conducted over many years, and the achievements one can expect in a single year are limited to the more quickly assessed, short-term aspects of their natural history.

Abstract
From February1997 – January 1998 we studied golden eagle occupancy, breeding success and movements in north-central Mexico. Initial surveys of the study area were performed, and nest sites were monitored for occupancy and breeding success. Few occupied nests sites were productive in 1997. In those that were, 1-2 nestlings were produced per successful attempt. Also, it appeared that there was a high turnover of breeders that might be linked to direct persecution or incidental poisoning. An attempt was made to capture golden eagles for radio- marking. The focus was on breeders, but we were also interested in fledglings and other age classes. During this time we radio-marked 7 golden eagles from 5 nesting areas with 401 MHz satellite-received Platform Terminal Transmitters (PTTs) and conventional (164 MHz) tail-mounted transmitters. When used in combination the two transmitter technologies allowed us to ground track individuals for behavioral observations (using conventional transmitters), and obtain ranging information on individuals if they left the immediate area of the nest nesting area (using the PTTs). Substandard components in the PTTs prevented the acquisition of the volume of location estimates that we had anticipated. However, we were able to determine that the breeding eagles were resident on their territories. The PTT on one eagle (14506) worked as expected. Simple range analysis revealed that at the 80% level the location estimates encompassed 59,419 ha. At the 40% level, 6,975 ha. were encompassed.

Methods
We searched the literature for information on Mexican golden eagles. Very little work has been published on eagles in Mexico; some studies have been conducted in Texas and Arizona, but are not very recent. Juan Vargas held considerable unpublished knowledge of some pairs.

A protocol was devised for the first year’s study. This was finalized in March of 1997. The aims for 1997 focused on the collection of data that would illuminate habitat requirements of golden eagles in Mexico. As in any study of wildlife, the protocol was flexible, and emphases could be shifted to accommodate conditions in the field. The aims were changed and superceded by events in the field, although the overall objectives remained the same.
Initial surveys

Ara biologists performed early surveys of eagle areas. ARA/Earthspan biologists then conducted surveys for golden eagle occupancy in north-central Mexico in the states of Nueva Leon, San Luis Potosi, Zacatecas, and Aguascalientes during February – July. We investigated reported sightings of breeding eagles and historical nests as well as surveying likely cliffs for nests. Other suspected sites were investigated. Surveys relied heavily upon the Juan Vargas’ experience and knowledge of local eagle sites.

Capture and Marking
Priority was given to the capture of individuals that were nesting, at sites that were most easily accessible by road, and at sites that would provide the most advantageous monitoring situation (in terrain that was not extremely severe). We attempted to trap a maximum of 9 eagles beginning May 1997, using dho-gazas surrounding a lure golden eagle (see Bloom 1987) or radio-controlled bownet with a lagomorph as a lure for breeders (Jackman et al. 1994), and hand-capture in nests for nestlings. We placed traps in view of habitual perch locations or along regularly used flight paths. Trap placement was usually made the night before the attempt. We observed traps from blinds placed at least 100m away. Attempts were not made earlier in the season because we might have disrupted the breeding effort; trapping of breeding birds during the nesting season should not occur before the chicks are about two weeks old. At this age eaglets begin to be able to thermoregulate, and trapping activities are less likely to have a direct impact on them. Ideally we wanted to attempt eagle capture when nestlings were 2-7 weeks of age. After that time, breeding eagles spend less time at the nest, and are harder to capture. We targeted individuals in occupied and productive nesting areas.

We instrumented each captured eagle with an approximately 100g backpack package including an 85g PTT 100 (Microwave Telemetry) Platform Terminal Transmitter (PTT; 401 MHz) and a 15-20g harness, as well as a 12-15 g conventional, tail-mounted transmitter (VHF;164 MHz). PTTs were attached in a backpack configuration with 12.5mm TeflonÒ ribbon (Bally Ribbon Mills, Bally, PA, USA) secured with copper tubes, crimped around the TeflonÒ ribbon. Conventional transmitters were attached to a newer feather with superglue or epoxy, and thread. The criteria that must be met for eagles to be radiotagged were: 1) the eagle must weigh > 3000g (at which point the transmitter and PTT would weigh <3% of the eagle’s body mass); 2) the eagle must have no injury that might be exacerbated by carrying the transmitters; and 3) the eagle must have hard-penned feathers to accommodate a tail-mounted transmitter. The field team was authorized to release any eagle for any reason if they thought the fitting of a transmitter might reduce the eagle’s survivability.

All eagles captured were measured and, where possible, sexed and aged. We took the following morphological measurements: mass (kg), beak depth (mm), culmen length (mm), hallux length (mm), wing chord (curved; cm), wing span (cm), and tail length (cm). Measurements will provide data on eagle flight biomechanics for a cooperative study with Prof. C. Pennycuick, Bristol University, UK. We drew approximately 3 ml of blood from some captured eagles. Each captured eagle was banded with a USFWS numbered band for individual identification.

Throughout the capture, measuring, and transmitter fitting process, all efforts were made to reduce the stress on the eagle. The field team had the authority to release any eagle thought to be unduly stressed.

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