We examined patterns in the use of landfills (rubbish dumps) in the Chesapeake Bay by Bald Eagles (Haliaeetus leucocephalus). Sites of solid waste landfills (n  =  72) were located using state databases. Satellite tracking data from 64 eagles were used to track eagle movements hourly during daylight and once at midnight to determine roosting locations (2007–2012). Landfill use varied significantly with age class, with hatch-year birds using landfills six times more often than adults and twice as often as third- and fourth-year birds. Hatch-year birds spent significantly more time at landfills than expected based on landfill area relative to the study area outside of landfills. The relationship between time of year and eagle presence at landfills was not significant, though the results suggest a peak in landfill use in the late fall. There was spatial variation in landfill use, with 10% of the landfills used by study birds receiving 75% of the total landfill use. Landfills within two km of communal roosts received significantly more eagle activity than landfills farther from communal roosting sites. If eagle presence at landfills is indicative of foraging at these sites, the results provide evidence that foraging strategies in Bald Eagles change with age. Landfills may serve as important scavenging sites for hatch-year and second-year eagles, whereas older birds may be more successful obtaining higher quality prey elsewhere.

Access to food resources is essential to self-maintenance and reproduction and, for species of conservation concern, foraging areas are considered critical habitat. Human disturbance is an important factor restricting access to prey resources for Bald Eagles (Haliaeetus leucocephalus) and guidelines in the Chesapeake Bay have been developed to mitigate its impact. However, our ability to implement such guidelines has been limited by a lack of information on important foraging areas. We used Brownian bridge movement modeling to develop a population-wide utilization probability surface for Bald Eagles along shorelines within the upper Chesapeake Bay. We used locations (n  =  320 304) for individuals (n  =  63) tracked with GPS satellite transmitters between 2007 and 2011 in the analysis. We examined seasonal variation by developing utilization surfaces for summer and winter. Although shoreline use was widespread, segments receiving high levels of activity were relatively rare. Shoreline classified as having the highest category of use and accounting for 10% of the total utilization made up 0.41% and 0.55% of the total shoreline for winter and summer, respectively. From a management perspective, there is a clear pattern of diminishing returns in conservation value for including sequentially lower-use shorelines in land-use management plans. Shoreline use shifted dramatically in both location and extent between seasons. During the summer months, use was highly concentrated on shorelines along the main stem of the Chesapeake Bay or along major (>1 km wide) tributaries. During the winter months, use shifted away from the main stem of the bay and was more focused on minor (<100 m wide) tributaries and inland ponds. Seasonal shifts in shoreline use suggest the need for season-based management objectives.

We analyzed counts from the annual Midwinter Bald Eagle Survey to examine state, regional, and national trends in counts of wintering Bald Eagles (Haliaeetus leucocephalus) within the conterminous 48 United States from 1986 to 2010. Using hierarchical mixed model methods, we report trends in counts from 11 729 surveys along 844 routes in 44 states. Nationwide Bald Eagle counts increased 0.6% per yr over the 25-yr period, compared to an estimate of 1.9% per yr from 1986 to 2000. Trend estimates for Bald Eagles were significant (P ≤ 0.05) and positive in the northeastern and northwestern U.S. (3.9% and 1.1%, respectively), while trend estimates for Bald Eagles were negative (P ≤ 0.05) in the southwestern U.S. (−2.2%). After accounting for potential biases resulting from temporal and regional differences in surveys, we believe trends reflect post-DDT recovery and subsequent early effects of density-dependent population regulation.

We describe results from a comprehensive effort to survey and monitor Peregrine Falcons (Falco peregrinus) breeding in Lake Mead National Recreation Area (LMNRA) from 2006–2010. We identified 37 breeding territories, and the annual occupancy rate averaged 94%. Pooled over time, breeding success was 72%, and average reproductive output was 1.8 young per nesting attempt. The closest distance between eyries from neighboring territories was 1.2 km; the lowest annual mean nearest-neighbor distance (NND) was 6.3 km. No relationship was apparent between NND and breeding success or reproductive output. Nesting attempts occurred twice as often in eyries with a north-facing (68%) aspect than in eyries with a south-facing (32%) aspect. Pairs using south-facing eyries began incubating 5 d earlier than those using north-facing eyries, although the difference was not statistically significant. On a finer scale, pairs most commonly selected northwest-facing eyries (45% of nesting attempts), despite experiencing a trend of lower mean breeding success (64%) than in eyries with aspects facing all other quadrants (83%). Within territories, peregrines used alternate eyries following 58% of nesting attempts; however, switching eyries between years did not influence breeding success. Peregrines appear to be largely year-round residents at LMNRA, based on monthly surveys at five territories during a nonbreeding season (August 2008 through January 2009). We also detected peregrines at 10 of 24 territories in September and October 2009 using 10-min call-broadcast surveys at eyrie cliffs. Our results contribute to knowledge of increasing populations of peregrines following the DDT era in the southwestern U.S., and provide insight about how reservoirs may influence local breeding populations.

After an absence of more than two decades, Peregrine Falcons (Falco peregrinus) resumed nesting in Ontario in 1986. Between 1991 and 2006, at least 193 young fledged in southern Ontario and 548 young fledged in northern Ontario. The number of breeding pairs, nesting attempts, successful nests, and young fledged all steadily increased in both regions throughout this period. In southern Ontario, 25% of the breeding adults produced nearly 50% of all fledglings, and 87% of the fledglings came from just eight breeding sites. Direction of natal dispersal was variable, but females consistently moved farther than males, and there was frequent movement both to and from adjacent American states. The population recovery resulted from the release of 592 captive-bred F. p. anatum juveniles in Ontario between 1977 and 2005, plus immigration from other provinces and release efforts in adjacent regions of the United States, where at least five subspecies contributed to the gene pool of captive-bred birds. Encounter rates for both captive-bred and wild-fledged young in Ontario have been low, but wild-raised young have been recruited to the breeding population almost twice as frequently as captive-bred birds. This difference partially explains the genetic composition of the southern Ontario population, where at most 21% of nesting attempts between 1995 and 2006 involved a pair of Canadian-released anatum adults, and 59% of cases involved at least one adult of American origin. Therefore, although the Ontario population has exceeded documented historical levels, it may not be greater than actual historical numbers, and it cannot be strictly considered an anatum population.

The Northern Goshawk (Accipiter gentilis) is currently listed as a sensitive species by the U.S.D.A. Forest Service. Previous research in our study area, the South Hills of the Minidoka Ranger District of the Sawtooth National Forest, Idaho, identified possible signs of parasite infections among the banded adult and nestling goshawks, which could influence their survival and breeding success. Therefore, we sought to quantify the prevalence and intensity of Leucocytozoon parasites among a sample of nestling goshawks in the South Hills during the 2012 breeding season. We sampled 27 nestlings from 12 nests for Leucocytozoon parasites by examining blood smears. All sampled nestlings were infected with Leucocytozoon parasites. The infection intensity ranged from 0.82–10.05 Leucocytozoon parasites per 1000 erythrocytes (mean ± SE  =  4.35 ± 0.54). Using site elevation, distance-to-water, nestling age, nestling sex and nest tree species as predictor variables for infection intensity by Leucocytozoon parasites, we employed an information theoretic approach to select a top model to determine the presence of an effect. The top model included nest tree species as the sole predictor for infection intensity. Specifically, higher Leucocytozoon parasite intensity was associated with quaking aspen (Populus tremuloides) nest trees, as compared to lodgepole pine (Pinus contorta). Further research will help identify management implications for this species of concern in this high altitude forest surrounded by a shrub-steppe ecosystem.

I studied the diet of the Golden Eagle (Aquila chrysaetos) in western Iran by identifying food items in prey remains, pellets, and video recordings at seven nests during the 2011–2013 breeding seasons. Two methods were used to calculate diet composition: minimum number of individuals of each prey species and estimated biomass for prey items. I identified 316 prey items, which included five species of birds, four species of mammals, and two species of reptiles. Mammals made up the greatest proportion of the diet, 44.0% by frequency and 76.8% by biomass, and birds accounted for 43.7% of the diet by frequency and 17.7% by biomass. Cape hare (Lepus capensis), Chukar (Alectoris chukar), Common Magpie (Pica pica), large-toothed souslik (Spermophilus fulvus) and common fox (Vulpes vulpes) were the most important prey species. The percentage of mammals in the Golden Eagle’s diet in western Iran was lower than in North America, Scotland, the mountains of the Mediterranean, and across Europe and Asia.