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Aechmophorus Occidentalis) Implanted with Intracoelomic Satellite Transmitters

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Aechmophorus Occidentalis) Implanted with Intracoelomic Satellite Transmitters Post-release Survival and Movement of Western Grebes (Aechmophorus occidentalis) Implanted with Intracoelomic Satellite Transmitters KYRA L. MILLS1,*, JOSEPH K. GAYDOS2, CHRISTINE V. FIORELLO1, EMILY R. WHITMER1, SUSAN DE LA CRUZ3, DANIEL M. MULCAHY4, L. IGNACIO VILCHIS5 AND MICHAEL H. ZICCARDI1 1Oiled Wildlife Care Network, Karen C. Drayer Wildlife Health Center, 1089 Veterinary Drive VM3B, School of Veterinary Medicine, University of California, Davis, California, 95616, USA 2SeaDoc Society, Karen C. Drayer Wildlife Health Center, University of California, Davis – Orcas Island Office, 942 Deer Harbor Road, Eastsound, Washington, 98245, USA 3U.S. Geological Survey, Western Ecological Research Center, 505 Azuar Drive, Vallejo, California, 94592, USA 4U.S. Geological Survey, Alaska Science Center, 4210 University Drive, Anchorage, Alaska, 99508, USA 5Division of Applied Animal Ecology, San Diego Zoo Institute for Conservation Research, San Diego, California, 92027, USA *Corresponding author; E-mail: [email protected] Abstract.—The main goal of this study was to gain knowledge on post-release survival and movement of Western Grebes (Aechmophorus occidentalis) using a modified technique for implanting satellite transmitters. This technique had improved post-surgical survival in an earlier study. Nine Western Grebes, implanted with intracoelomic (within the body cavity) satellite transmitters with percutaneous antennae, were released close to their capture site in San Francisco Bay, California, USA. Eight survived at least 25 days (average number of transmittal days was 140.8), while two had transmitters that provided data for greater than 1 year (436 and 454 days). The average cumulative distance recorded for all Western Grebes (n = 9) was 829 km with two round-trip movements documented. One individual Western Grebe traveled a cumulative round-trip distance of 2,144 km in July and November 2011, while another individual traveled a round-trip distance of 1,514 km between 8 and 14 December 2011. This study provides a step forward in testing implantable satellite transmitters in Western Grebes and highlights the need to further improve tracking methods, potentially improving our understanding of their population threats. Received 5 February 2015, accepted 25 March 2015. Key words.—Aechmophorus occidentalis, migration, satellite transmitter, surgical implantation, Western Grebe. Waterbirds 39(2): 175-186, 2016 Over the past two decades, Western 2011; 1,071 for Cosco Busan oil spill, Cosco Grebe (Aechmophorus occidentalis) popula- Busan Oil Spill Trustees 2012). Also, there tions have been in decline along the west is evidence that low volume oil spills regu- coast of North America (Ivey 2005; Ander- larly kill small numbers of wintering Western son et al. 2009; Wilson et al. 2013). Multiple Grebes throughout their range (Speich and and synergistic factors have been hypoth- Wahl 1986; Henkel et al. 2014). According esized to explain this rangewide decline. to stranding reports and rehabilitation re- One hypothesis is oil spill-related mortal- cords in California, USA, most Western and ity of wintering adults (Carter et al. 2003; Clark’s grebe mortality caused by oil injury Hampton et al. 2003; Humple et al. 2011). (either via a declared spill, natural seep, or Large spills off the western coasts of the USA unknown source) occurs between Novem- have killed thousands of Western Grebes ber and February. One likely contributing (Smail et al. 1972; Page et al. 1990; Carter factor in the susceptibility of Aechmophorus 2003; Humple et al. 2011). For example, spp. to marine oil spills is the large percent- both the 2005 Ventura Oiled Bird Incident age of adult Western and Clark’s grebes that and the 2007 Cosco Busan oil spill resulted undergo simultaneous flight feather molt in heavy estimated mortality of Western during the non-breeding season, when they and Clark’s (A. clarkia) grebes (2,500 for are wintering along the Pacific coast of the Ventura Oiled Bird Incident, Humple et al. USA (Humple et al. 2013). 175 176 WATERBIRDS Our understanding of potential fac- age, although aging Western Grebes is intrinsically dif- tors contributing to the decline of Western ficult (Pyle 2008; Humpleet al. 2013). We determined the sex of the birds (Table 1) based on culmen length Grebes is hampered by a lack of detailed in- (La Porte et al. 2013) and obtained body weights at the formation on migratory patterns and winter time of capture and daily thereafter while in captivity. habitat use. Few data exist on winter move- On the day of capture, we transported all birds ment patterns and migratory routes for (placed inside plastic carriers on elevated net plat- these animals, yet data on migration and forms) from the location of capture to a research facili- ty about 120 km away. Birds were housed indoors in 3-m winter movement are needed to determine diameter freshwater rehabilitation pools with a depth potential exposure to oil spills and to guide of 1.3 m; pool water temperature and air temperature mitigation projects after spills. To date, were maintained at 16 °C and 18 °C, respectively. We movement data have only been available via force-fed birds three to six whole, freshly thawed night band returns from rehabilitated oiled and smelt (Spirinchus starksi) or capelin (Mallotus villosus) twice daily (approximately 120 g total/bird/day). To non-oiled released birds (Humple and Hol- prevent infection by the fungus Aspergillus sp., we ad- comb 2014). External or internal telemetry ministered oral itraconazole (15 mg/kg; Sporanox) devices and satellite transmitters can provide at the time of capture and once daily until release. To species’ movement information; however, manage pain associated with capture and surgery, we unlike several other marine bird species that administered oral meloxicam (0.5 mg/kg; Metacam, Boehringer Ingelheim Vetmedica) upon capture and are readily tracked, evidence from diving once daily until release. All birds received one dose of bird species (Calvo and Furness 1992; With- an oral multivitamin supplement (Sea Tabs) during the ey et al. 2001; Ropert-Coudert et al. 2007) course of the trial. suggests that externally attached devices are While in captivity, we identified grebes individually not always well tolerated. Furthermore, pilot with temporary plastic leg bands, which were replaced with permanent U.S. Geological Survey metal leg bands studies have suggested that surgical implan- prior to release. Post-surgery birds were placed in car- tation of transmitters, while an improved riers with a net bottom for 1-4 hr while they recovered alternative for some species not handling from anesthesia. While in captivity birds were examined externally attached transmitters (Korschgen daily by a veterinarian and were kept in captivity for a to- et al. 1996), is also challenging in Western tal of up to 48 hr, after which they were released within 3 km of their capture location. Grebes. Previous attempts to use the Korsch- gen et al. (1996) procedure for transmitter Clinical Pathology implants in Western Grebes in 2004 and On the day of capture and back at the facility, we col- 2005 resulted in 100% mortality. A modifica- lected a blood sample (up to 2.5 mL) from the jugular tion to this surgical technique (Gaydos et al. vein for the evaluation of blood parameters. Blood pa- 2011) successfully reduced the immediate rameters examined were: corticosterone level, plasma protein electrophoresis profile, complete blood count post-implantation mortality in a captive set- (packed cell volume, total white blood cell count, white ting, but field survival was not assessed. cell differential), and plasma chemistry. Plasma chemis- Our primary goal was to evaluate post-re- try included fibrinogen, glucose, blood urea nitrogen, lease survival of Western Grebes implanted creatinine, sodium, potassium, total carbon dioxide, with satellite transmitters, using the modi- amylase, lipase, calcium, phosphorus, cholesterol, tri- glycerides, uric acid, aspartate aminotransferase, ala- fied surgical technique described in Gaydos nine aminotransferase, lactate dehydrogenase, creatine et al. (2011). A second goal was to gain new phosphokinase, and gamma-glutamyl transpeptidase. information on Western Grebe movements. All clinical pathology was processed at a veterinary hos- pital and laboratory in California, USA. We anesthetized all birds with 5% isoflurane via METHODS mask, maintained between 2-5% in 100% oxygen. Us- ing a previously described procedure (Gaydos et al. Study Area 2011), we implanted birds with Argos Platform Termi- nal Transmitters (PTT; Argos 2013) with external per- We captured Western Grebes (n = 9) from three cutaneous whip antennae. The basic surgical technique locations in the northern region of San Francisco Bay, is described in detail in Gaydos et al. 2011; modifications California, USA, on 7 and 9 December 2010 using a included: 1) providing each bird with 30 cc of lactated modified neutrally buoyant gill net technique (Breault ringer solution subcutaneously during surgical prepa- and Cheng 1990). Based on plumage characteristics, we ration; 2) administering meloxicam for pain; 3) not believed that all captured birds were after hatch year in removing feathers at the incision site; 4) lateral offset- IMPLANTED WESTERN GREBE SURVIVAL 177 ting of the body wall incision approximately 1 cm to the right of the midline; 5) application of a waterproof seal- ant to the antenna exit site; 6) application of a 1 cm2 square piece of dry porcine
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