Marco Restani

Funding Extinction? Biological Needs and Political Realities in the Allocation of Resources to Endangered Species Recovery

O nation’s endangered species require implementation of scientifically based recovery actions to attain sustainable population sizes and to avert extinction. Crafting recovery approaches is often politically contentious and scientifically challenging, but it proceeds reasonably well through the writing of legislated recovery plans. Implementation of planned recovery strategies, however, is much more difficult because it often curtails resource use by humans and requires adequate funding. Implementation decisions ultimately are made by the US Fish and Wildlife Service (FWS) and the National Marine Fisheries Service (NMFS), both of which are tasked with administering the Endangered Species Act (ESA). However, many stakeholders with conflicting goals, differing reward structures, and varying routes of influence are wedded to implementation decisions (Figure 1). Those stakeholders—a public composed of resource users and stewards; a Congress seeking political gain; federal agencies tasked with conserving biodiversity, set within departments that are expected to make natural resources available; and states that must curtail their residents’ activities to achieve national goals—find it difficult to reach consensus (EasterPilcher 1996, Czech and Krausman 2001). As a result, recovery spending may not match agencies’ stated recovery needs (USGAO 1988, Simon et al. 1995, Restani and Marzluff 2001). Species favored by the public or Congress, for example, might garner sufficient funds for many recovery actions, while species with less robust sponsorship go without funds and perish from neglect. For example, failure to remove exotic brown tree snakes (Boiga irregularis) from Guam (a US territory with Marco Restani (e-mail: restanim@rocky.edu) is an assistant professor in the Department of Biology, Rocky Mountain College, Billings, MT 59102. He is an avian ecologist who specializes in predator–prey interactions, migration and dispersal, and habitat selection. His research involves conservation of sensitive and endangered species, usually raptors, across multiple-use landscapes. John M. Marzluff is associate professor of Wildlife Science in the College of Forest Resources, University of Washington, Seattle, WA 98195. He is an ecologist with broad interests in land-cover change, endangered species conservation, the biology of corvids, and responses of birds to human settlement and forestry. He currently directs an interdisciplinary research and education program in urban ecology at the University of Washington and conducts research on how the pattern of urban sprawl affects the abundance, survival, and reproduction of birds.

EFFECTS OF ANTHROPOGENIC FOOD SOURCES ON MOVEMENTS, SURVIVORSHIP, AND SOCIALITY OF COMMON RAVENS IN THE ARCTIC

Abstract We investigated survivorship, movements, and sociality of Common Ravens (Corvus corax) exploiting concentrated food resources at a landfill in Greenland. From 1992–1995 we banded 383 ravens: 365 were captured at the landfill and 18 were banded in nearby nests. Thirty-nine ravens were recovered, most by shooting (87%). Mean number of days survived post-banding (494 ± 97) did not differ among age groups, but a higher proportion of juveniles was recovered. Ravens migrated west and south to the coast during winter. No difference existed among age groups in mean distance between locations of banding and recovery (151 ± 31 km). Number of ravens congregating at the landfill declined during the study, coinciding with a decrease in the local human population. Harsh winter climate, limited ice-free land, and abundant human refuse influenced raven use of the wilderness landscape by facilitating the formation of large, nomadic foraging groups.

SURVIVAL AND MOVEMENTS OF JUVENILE BURROWING OWLS DURING THE POSTFLEDGING PERIOD

Abstract Burrowing Owl (Athene cunicularia) populations have declined extensively throughout much of North America, and modeling demography may assist conservation. However, few studies have estimated adult survival, and fewer still have determined juvenile survival. In 2003 and 2004 we monitored survival of 40 radio-tagged juveniles during the postfledging period in the Little Missouri National Grassland, North Dakota, where owls nested in black-tailed prairie dog (Cynomys ludovicianus) colonies. Survival averaged 0.57 (95% CI: 0.41–0.73) prior to autumn migration. Mortality was highest during the first two weeks after nest departure when juveniles were flightless, and two to three weeks later when juveniles became independent. Predation or starvation was implicated in most deaths. Distribution and abundance of escape cover (number of prairie dog burrows within 30 m of nests and size of the natal prairie dog colony) did not affect survival. Body condition and brood size at the time of radio-tagging also did not influence survival. Juvenile owls exhibited nest-centered dispersal, and averaged 108 ± 21 (SE) m and 82 ± 17 m from nests at initiation of migration in 2003 and 2004, respectively. Mean dates of departure from the study area were 2 September (± 3 days) 2003 and 24 August (± 2 days) 2004. Mortality during the postfledging period accounted for approximately two-thirds of mortality in the first year of life.

LEAD, MERCURY, SELENIUM, AND OTHER TRACE ELEMENTS IN TISSUES OF GOLDEN EAGLES FROM SOUTHWESTERN MONTANA, USA

Lead-based rifle bullets, used in game hunting and recreational shooting, fragment when striking bone and soft tissues. Lead fragments may be ingested by birds scavenging offal piles or nonretrieved carcasses and therefore pose a poisoning risk. We captured and sampled 74 Golden Eagles (Aquila chrysaetos) in southwestern Montana, USA, from 2008 to 2010 to evaluate levels of lead, mercury, selenium, and 13 other trace elements in blood and feathers. Lead was detected in blood of most (97%, n=70) eagles; mean blood level was 0.26 parts per million (ppm). Most eagles (65%) had background levels (<0.2 ppm), 29% had elevated levels (0.2–0.5 ppm), 13% had chronic levels (0.51–1.0 ppm), and 3% had acute levels (>1.0 ppm) in blood. Lead in blood decreased from winter to spring. Resident eagles had higher lead levels than eagles of unknown residency. Mercury was detected in few eagles, whereas selenium was detected in all, but at a low level (0.36 ppm). Other chemical elements in blood were at low or biologically appropriate levels. Lead in feathers (n=29) was correlated with blood lead (P=0.010), as was mercury in blood and feathers (n=48; P=0.003). Concentrations of lead and mercury in feathers were higher in adults than in juveniles and immatures (P<0.016) and both elements tended to increase with age. Selenium in feathers (n=48) appeared stable across plumage classes. Although detection rates of lead in blood of eagles captured in spring increased from 1985–1993 to 2008–2010, mean levels decreased (P<0.023) between periods, as did proportions of eagles exhibiting above background levels (>0.2 ppm; P<0.02).

Sylvatic plague reduces genetic variability in black-tailed prairie dogs.

Small, isolated populations are vulnerable to loss of genetic diversity through inbreeding and genetic drift. Sylvatic plague due to infection by the bacterium Yersinia pestis caused an epizootic in the early 1990s resulting in declines and extirpations of many black-tailed prairie dog (Cynomys ludovicianus) colonies in north-central Montana, USA. Plague-induced population bottlenecks may contribute to significant reductions in genetic variability. In contrast, gene flow maintains genetic variability within colonies. We investigated the impacts of the plague epizootic and distance to nearest colony on levels of genetic variability in six prairie dog colonies sampled between June 1999 and July 2001 using 24 variable randomly amplified polymorphic DNA (RAPD) markers. Number of effective alleles per locus (ne) and gene diversity (h) were significantly decreased in the three colonies affected by plague that were recovering from the resulting bottlenecks compared with the three colonies that did not experience plague. Genetic variability was not significantly affected by geographic distance between colonies. The majority of variance in gene frequencies was found within prairie dog colonies. Conservation of genetic variability in black-tailed prairie dogs will require the preservation of both large and small colony complexes and the gene flow among them.

Effects of Supplemental Food and Experience on Winter Survival of Transplanted Wild Turkeys

Abstract Wildlife biologists have provided supplemental food during winter to improve post-release survival of Wild Turkeys (Meleagris gallopavo) transplanted north of their ancestral range in Minnesota. We evaluated the effectiveness of this action by monitoring overwinter and annual survival of 140 transplanted turkeys on three supplemental food and three control study areas in 2004 and 2005. Both winters of study were mild relative to historic snowfall levels and temperature. Patterns of mortality during winter were consistent across years with most mortalities occurring on control study sites. Turkeys that had been released in the prior year and survived until January of the current year had little mortality, regardless of supplemental food. The relative risk of death estimated from proportional hazards models for turkeys at supplemental food sites relative to those at control sites during winter was 5.0 in 2004 and 9.7 in 2005. Estimates of relative risk for newly released relative to experienced turkeys during winter were 9.4 in 2004 and 12.6 in 2005. Site-to-site variability in risk decreased during the non-winter period with treatment and control sites having more similar risk levels. Ninety-one turkeys died and mammalian predation was the most common cause of known mortality.