Migratory shorebird and vegetation evaluation of Chickaloon Flats, Kenai National Wildlife Refuge, Alaska
Date
2012
Authors
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Publisher
University of Delaware
Abstract
I conducted my research on Chickaloon Flats, Kenai National Wildlife Refuge, which is a tidal mudflats located along the northern part of the Kenai Peninsula in upper Cook Inlet, Alaska, 2009–2010. It is a protected coastal estuary stopover area along the Pacific Flyway, covering 7% of the total estuarine intertidal area of Cook Inlet and Prince William Sound. Almost one-third (23 of 73) of shorebird species recorded in Alaska use this stopover during spring and/or fall migrations. My objectives included 1) creating a current vegetation classification map and quantify vegetation changes from 1975 to 2005, 2) identify the driving factors of ephemeral pool presence, 3) document avian use of Chickaloon Flats during migration periods, and 4) conduct a multi-isotopic approach to estimate probable breeding and/or wintering origins of six species of shorebirds using Chickaloon during spring and fall migration of 2009 and 2010.
I analyzed Hydrogen (dD), Carbon (d13C), and Nitrogen (d15N) isotopes from feathers and performed a likelihood-based assignment to inform North American (NA) and South American (SA) origins of six shorebird species. Only lesser yellowlegs feathers (Tringa flavipes) indicated wintering (n=4, coastal SA) and breeding (n=26, central Alaska) ranges. Estimated wintering ranges for least sandpipers (Calidris minutilla, n=13) occurred in southern NA to northern SA, long-billed dowitchers (Limnodromus scolopaceus, n=8) occurred in Mexico, and pectoral sandpipers (Calidris melanotos, n=11) occurred in northeastern SA. Estimated breeding ranges for greater yellowlegs (Tringa melanoleuca, n=67) occurred in southwest Alaska, and short-billed dowitcher (Limnodromus griseus caurinus, n=26) occurred in south-central Alaska. The analysis of stable isotopes to infer molt origins of birds is a useful and important tool in migration and conservation studies. I determined probable origins of long-distance shorebird migrants, some of high conservation concern, using an Alaskan stopover site, which identified habitats and previously unknown areas used by Alaskan breeding shorebirds.
I observed 95 bird species throughout the spring and fall of 2009 and 2010, with 26 of those species breeding on Chickaloon. I observed several pulses of total birds during spring migration, and a more protracted fall migration with variable smaller pulses of birds. Estimated maximum daily shorebird numbers are 5,638 during spring migration, and 20,297 during fall migration.
I created a recent vegetation classification of 7 vegetation types on Chickaloon Flats using 2005 Landsat TM imagery. I also quantified change of 3 mud/vegetation cover types from 1975–2005. The vegetated community type remained relatively stable over the 30-year period, while the mud and mixed mud/vegetation cover types closest to Cook Inlet showed a relatively-small amount of change over time. The greatest change was an increase in mud area, indicating that the vegetated areas of Chickaloon may be slowly converting to a less productive mud community type. My research highlights the overall importance and value of Chickaloon Flats as a stopover and breeding grounds for a diversity of avian species, and long-distance migrant shorebirds in particular.