Survey of Cliff-Nesting Raptors, Dalton Highway Management Unit, Alaska, 1999-2002
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U. S. Department of the Interior BLM-Alaska Open File Report 89 Bureau of Land Management BLM/AK/ST-03/009+6501+024 September 2003 Alaska State Office 222 West 7th Avenue Anchorage, Alaska 99513 Survey of Cliff-Nesting Raptors, Dalton Highway Management Unit, Alaska, 1999-2002 Tim Craig and Cindy Hamfler Cover Photo Adult and juvenile golden eagle at a nest site within the study area (photo by Tim Craig). Authors Tim Craig is the Wildlife Biologist for the Dalton Highway Management Unit in the BLM-Alaska Northern Field Office. Cindy Hamfler is a Wildlife Biology Technician in the same office. The BLM Mission The Bureau of Land Management sustains the health, diversity and productivity of the public lands for the use and enjoyment of present and future generations. Disclaimer The mention of trade names or commercial products in this report does not constitute endorsement or recom- mendation for use by the federal government. Open File Reports Open File Reports issued by the Bureau of Land Management-Alaska present the results of inventories or other investigations on a variety of scientific and technical subjects that are made available to the public outside the formal BLM-Alaska technical publication series. These reports can include preliminary or incomplete data and are not published or distributed in quantity. The reports are available while supplies last from BLM External Affairs, 222 West 7th Avenue #13, Anchorage, Alaska 99513, telephone (907) 271-5555; and from the Juneau Minerals Information Center, 100 Savikko Road, Mayflower Island, Douglas, AK 99824, (907) 364-1553. Copies are also available for inspection at the Alaska Resource Library and Information Service (Anchorage), the USDI Resources Library in Washington, D. C., various libraries of the University of Alaska, the BLM National Business Center Library (Denver) and other selected locations. A complete bibliography of all BLM-Alaska scientific reports can be found on the Internet at: http:// www.ak.blm.gov/affairs/sci_rpts.html. Related publications are also listed at http://juneau.ak.blm.gov. Survey of Cliff-Nesting Raptors, Dalton Highway Management Unit, Alaska, 1999-2002 Tim Craig and Cindy Hamfler BLM-Alaska Open File Report 89 September 2003 U. S. Department of the Interior Bureau of Land Management Abstract We surveyed the central portion of the Bureau of Land Management’s Dalton Highway Management Unit (DHMU) for cliff-nesting raptors and ravens from 1999 to 2002. We primarily used helicopters to conduct the search and found 76 unoccupied and 17 occupied nests. More raptors and raven nest sites occured in the Dietrich River Valley, which is the more mountainous, cliff-rich section of the study area. This information will provide population data to help land managers make informed land-use decisions in the future. Acknowledgments Special thanks to: John Payne, BLM-Alaska State Office, for providing funding; the U.S. Fish and Wildlife Service-Kanuti National Wildlife Refuge for providing river transportation; Randi Jandt for assisting in survey work; Erica Craig, Craig McCaa, and Jim Herriges for editorial comments. i Table of Contents Abstract ............................................................................................................................................... i Acknowledgments ............................................................................................................................... i Introduction ........................................................................................................................................ 1 Study Area.......................................................................................................................................... 1 Methods ............................................................................................................................................. 2 Results ............................................................................................................................................... 4 Occupied Stick Nests ...................................................................................................................... 4 Occupied Ledges/Cavities .............................................................................................................. 7 Unoccupied Stick Nests .................................................................................................................. 7 Discussion .......................................................................................................................................... 7 Literature Cited................................................................................................................................. 10 Figures Figure 1. Area surveyed for cliff-nesting raptors in the central portion of the Dalton Highway Management Unit, Alaska, 1999-2002 ........................................................................ 3 Figure 2. Locations of occupied and unoccupied raptor nests on cliffs in the central portion of the Dalton Highway Management Unit, Alaska, 1999-2002 ........................ 6 Figure 3. Density of unoccupied stick nests used by cliff-nesting raptors in the central portion of the Dalton Highway Managment Unit, Alaska, 1999-2002 .............. 8 Tables Table 1. Occupied and unoccupied nests found on inventories of raptor cliff nests in the central part of the Dalton Highway Management Unit, Alaska, 1999-2002. ...... 5 ii Introduction Study Area The Bureau of Land Management (BLM) is The DHMU encompasses about 1,127066 ha responsible for management of public lands adjacent to the Dalton Highway. This study along the Dalton Highway and adjacent Trans occurred in approximately the central third of Alaska Pipeline System (TAPS) between the the DHMU (Figure 1) and included the foothills Yukon River and the Arctic Coastal Plain. The and mountains of the Brooks Range south of BLM unit that administers this land is the Chandalar Shelf (circa 68 ° 02’N) and north of Dalton Highway Management Unit (DHMU). the Kanuti River (circa 66 ° 22’N). While most of the survey effort was spent on BLM Raptor surveys have been conducted by other administered lands, we also surveyed small agencies on land they administer adjacent to segments of adjacent land that is administered BLM lands in the general area (Swanson 1991). by the State of Alaska (9045 ha) or other federal In addition, inventories of raptors that nest in agencies (7726 ha) when cliffs on these lands close proximity to the TAPS have been were located very close to the BLM boundary or conducted several times in the past (Roseneau were continuous across administrative and Bente 1979, Roseneau 1980, USFWS boundaries. In total we surveyed about 603,347 records, Bob Ritchie, pers. comm.). However, ha during this work. BLM-administered lands in the DHMU range over 20 miles beyond the TAPS and to our Five major river valleys and their tributaries knowledge no thorough inventory of cliff incise the study area: the Jim, Bettles, Dietrich, nesting raptors has been conducted on all BLM and Middle and South Fork Koyukuk Rivers. lands in the DHMU in recent years. These mountain valleys host a variety of undisturbed habitats native to interior Alaska In 1999 the Northern Field Office of the Alaska including montane tundra communities, shrub- BLM began searching for cliff-nesting raptors in dominated riparian areas and patchy coniferous the southern Brooks Range in the central portion and deciduous forests. of the DHMU. This effort was driven by agency policy in fulfillment of the Federal Land Policy The topography in the study area ranges from and Management Act (FLPMA) of 1976. This rolling, tundra-covered hills in the south (base law requires that the BLM manage public lands elevations over 425 m), to glacier-carved for multiple use and sustained yield of natural mountain valleys divided by flat-bottomed resources and requires that an inventory of all riparian areas in the north (peak elevations over public lands, their resources, and other values be 1200 m). Cliffs are strewn sporadically prepared and maintained on a continuing basis throughout the study area. These cliffs range in (Olendorff and Kochert 1992). As part of this size from short (less than 100 m tall), isolated mandate, Bureau policy directs that wildlife monoliths called “tors” in the southern foothills inventories and monitoring be performed in to massive escarpments more than 500 m tall in order to collect information on which to base the mountainous northern part of the study area. management strategies and to assist in The exposed lithic material that is available to evaluation of implementation of land-use nesting raptors in the study area includes decisions (Olendorff et al.1989). limestone/marble and granite cliffs and eroded alluvial bluffs that occur along watercourses. 1 Warm temperatures and continuous daylight 7 July 2002. In all, we spent about 20 hours and characterize the study area’s arctic climate in the 20 min. in aerial surveys, including ferry time summer and contrast with extreme cold within the study area. temperatures and abbreviated light in the winter. Average Wiseman, Alaska temperatures in July Resource managers commonly use helicopters (central to the study area) were 14 ° C, while to search for cliff-nesting raptors (Fuller and average temperatures in January were –27 ° C Mosher 1987) because they are effective in (Natural Resources Conservation Service, inaccessible country and provide