North American Bird Bander Apr-Jun 2016 Vol. 41 No. 2

Feature Articles

Using Outer Iris Color to Age Wrentits: An Evaluation.

Walter H. Sakai

Abstract- The Wrentit (Chamaea fasciata) is the quintessential and most common bird of the scrub land community of California.  Wrentits are monomorphic and uniform in size and plumage, making it difficult to age.  Ageing is primarily done by skull ossification and the outer iris color, which is brown in hatching-year birds, turning to maroon in after-hatching-year birds.  Using paint chips for comparison, I found that determining outer iris color was difficult for banders to determine and was not a reliable method to determine age in Wrentits.

 

Fall Migration and Wintering Areas of First Year Herring Gulls from the Western Basin of Lake Erie.

Bruce Buckingham

Abstract- Herring Gull (Larus argentatus) populations in the lower Great Lakes are declining.  Knowledge of the migration patterns and wintering areas of gulls may provide insight to where management efforts may be best applied.  Nesting Herring Gulls were banded in three colonies in the western basin of Lake Erie from 1981-2015 to determine their migration patterns and wintering areas.  The main wintering areas for the gulls was located in eastern Lake Erie.  Two other areas were noted along the Chesapeake Bay to New Jersey coastline and the western part of the Gulf of Mexico.  Band recoveries showed three possible migration routes: the Saint Lawrence Seaway, overland through central New York, and the Ohio/Mississippi River system.  Efforts to stabilize the Lake Erie Herring Gull population should be focused on the Lake Erie breeding colonies.