Use of Communal Roosts and Foraging Areas by Bald Eagles Wintering in the Klamath Basin

Keister, George P.; Anthony, Robert G.; O'Neill, Edward J.

doi:10.2307/3801028

Cited by 14 publications

(26 citation statements)

References 3 publications

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“…The Bear Valley Roost encompasses 254 ha of mixed-conifer forest located 4 km north of the Oregon-California border in Klamath County, Oregon (Keister and Anthony 1983). Vegetation at this site closely resembles the mixed-conifer-snowbrush (Ceanothus spp.…”

Section: Study Areamentioning

confidence: 99%

“…Searches for castings were done during plot sampling and indicated that castings persisted in a roost for >1 year (Keister and Anthony 1983). Thus, the presence of castings near a tree represented use for at least 2 years.…”

Section: Roost Treesmentioning

confidence: 99%

“…Our study builds on the earlier work (Keister and Anthony 1983) and examines use of roosting locations by bald eagles on 3 spatial scales:…”

mentioning

confidence: 99%

“…Overall results of their study indicated that eagles used the tallest (>25 m) trees with open branching patterns (e.g., trees with dead tops or snags) and used Douglas-fir in greater proportion than availability. While the original study focused primarily on roost-tree characteristics, other factors also may influence selection of roosting locations, including roost microclimate (Keister and Holbo 1985), proximity of a roost to food sources (Keister and Anthony 1983), and sociobehavioral interactions among roosting eagles (Stalmaster 1987). The importance of such factors in eagle habitat selection may be more effectively described using multiscale analyses (Stohlgren 1993, Stohlgren andFarmer 1994), particularly if eagles select habitat at various spatial scales (Chandler et al 1995).…”

mentioning

confidence: 99%

“…Fish and Wildlife Service 1978). In an earlier study of eagle habitat use at this roost, Keister and Anthony (1983) compared the density, diameter, height, age, and tree structure class of individual roost trees to the forest stand (roost). Overall results of their study indicated that eagles used the tallest (>25 m) trees with open branching patterns (e.g., trees with dead tops or snags) and used Douglas-fir in greater proportion than availability.…”

mentioning

confidence: 99%

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Management of Bald Eagle Communal Roosts in Fire-Adapted Mixed-Conifer Forests

DellaSala¹,

Anthony²,

Spies³

et al. 1998

The Journal of Wildlife Management

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Section: Study Areamentioning

confidence: 99%

Section: Roost Treesmentioning

confidence: 99%

“…Our study builds on the earlier work (Keister and Anthony 1983) and examines use of roosting locations by bald eagles on 3 spatial scales:…”

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Management of Bald Eagle Communal Roosts in Fire-Adapted Mixed-Conifer Forests

DellaSala¹,

Anthony²,

Spies³

et al. 1998

The Journal of Wildlife Management

Self Cite

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Mapping bald eagle activity shadows around communal roosts

Watts

Turrin

2017

J Wildl Manag

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We assessed diurnal activity patterns associated with communal roosts (n ¼ 26) by tracking nonbreeding bald eagles (Haliaeetus leucocephalus; n ¼ 58) within the upper Chesapeake Bay, USA, 2008-2013. We used daytime locations (n ¼ 54,165) to map activity shadows (using home range analytics, 90% kernel) around communal roosts, to evaluate the spatial structure and to delineate diurnal activity centers. We overlaid a range (100-3,200 m) of buffers around the perimeter of each roost to estimate the benefits of management scenarios in extending protection to daytime activities. Activity shadows around roosts varied from 1.5 km 2 to 116 km 2 ( x ¼ 30.3 AE 5.48 [SE]), reflecting landscape context. Roosts with small (<10 km 2 ) activity shadows tended to have simple shapes with roosts centrally located and positioned along primary shorelines. Roosts supporting large (>50 km 2 ) activity shadows tended to have complex shapes with roosts not centrally located and set back from primary shorelines. Daytime locations were highly concentrated in areas near communal roosts (76% of locations within 2 km of roost perimeters). Diurnal activity centers (n ¼ 38) included areas surrounding roosts and secondary activity centers that were primarily located along prominent shorelines. Communal roosts play a more significant and multi-faceted role in the eagle life cycle than we previously understood. Many of the roosts positioned along the shoreline provided resting places during the night and day, served as social gathering places during the day, and functioned as feeding locations. Evaluation of management buffers supports current management guidelines that recommend the establishment of 800-m buffers. Establishment of 800-m buffers within the study area would enclose 54% of all daytime locations, 66.7% of the area enclosed within activity centers associated with roosts, and 12.1% of the area enclosed in secondary activity centers. Ó 2017 The Wildlife Society.

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Structure and resilience of bald eagle roost networks

Watts

Dyer

2018

Wildl. Soc. Bull.

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The recognition that communal roosts are important elements within the life cycle of bald eagles (Haliaeetus leucocephalus) led to their protection under the "disturb" clause of the Bald and Golden Eagle Protection Act. The regular roost-switching movements of bald eagles imply that roosts are part of an interactive network where roosts represent nodes linked by birds moving between them. Network analysis holds promise for informing management decisions by assessing the effect of roost removal on the resilience of the broader network. We tracked nonbreeding bald eagles (n ¼ 56) within the upper Chesapeake Bay (2008)(2009)(2010)(2011)(2012)(2013), USA, to evaluate roost characteristics and network structure. We used midnight locations (n ¼ 14,464) to assess the use of communal roosts (n ¼ 212) and movement of birds among roosts (n ¼ 2,634) on successive roost nights to evaluate the pattern and strength of connections. We performed a sensitivity analysis to assess the response of the roost network to roost loss. Structure of the roost network approximated that of a scale-free network where the distribution of connections follows a power law of the form P(k) ¼ Ak Àg and g ¼ 1.1. Unlike random networks, connections within scale-free networks are concentrated within a few highly connected nodes (hubs). These hub roosts serve as bridges between large numbers of other roosts, have the shortest travel times to other roosts and greatest overall influence on network functioning. The effect of roost removal on overall network function was directly proportional to the connectivity of the roost being removed. The targeted removal of the majority (>90%) of roosts had very little effect on the network. Network sensitivity was high in response to the loss of roosts within the highest 10% of connectivity. This small (n ¼ 18) subset of roosts makes a disproportionate contribution to network function and the protection of these roosts should be a stated management objective with high priority. Network analysis represents a powerful tool with the potential to inform management decisions. Ó 2018 The Wildlife Society.

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Use of Communal Roosts and Foraging Areas by Bald Eagles Wintering in the Klamath Basin

Cited by 14 publications

References 3 publications

Management of Bald Eagle Communal Roosts in Fire-Adapted Mixed-Conifer Forests

Management of Bald Eagle Communal Roosts in Fire-Adapted Mixed-Conifer Forests

Mapping bald eagle activity shadows around communal roosts

Structure and resilience of bald eagle roost networks

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