Title of Oral/Poster Presentation

Factors influencing the fall migration of eared grebes from Great Salt Lake

Presenter Information

Maureen FrankFollow
Mike ConoverFollow

Class

Article

Department

Wildland Resources

Presentation Type

Oral Presentation

Abstract

Many bird migrations occur at night and therefore are difficult to observe. Radar stations designed to track weather can detect large migrations, which may then be viewed as digitally-recorded radar data. In radar images, migratory birds can be distinguished from weather by their shape and their movement relative to the direction of wind. Every fall, millions of eared grebes (Podiceps nigricollis) arrive at Great Salt Lake to feed on brine shrimp (Artemia franciscana). Brine shrimp are abundant in Great Salt Lake and this prey source allows eared grebes to substantially increase their body mass before migrating south. When eared grebes depart from Great Salt Lake, they consistently appear on nearby weather radar as a south-bound column that passes between the mountain ranges south of the lake. We analyzed radial velocity radar data to determine fall departure dates of eared grebes from Great Salt Lake during the migration periods of 1999 to 2013. Previous studies hypothesized that brine shrimp availability or weather may influence the departure of eared grebes. We examined these and other environmental variables that may affect timing of eared grebe departure.

Start Date

4-9-2015 1:00 PM

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Apr 9th, 1:00 PM

Factors influencing the fall migration of eared grebes from Great Salt Lake

Many bird migrations occur at night and therefore are difficult to observe. Radar stations designed to track weather can detect large migrations, which may then be viewed as digitally-recorded radar data. In radar images, migratory birds can be distinguished from weather by their shape and their movement relative to the direction of wind. Every fall, millions of eared grebes (Podiceps nigricollis) arrive at Great Salt Lake to feed on brine shrimp (Artemia franciscana). Brine shrimp are abundant in Great Salt Lake and this prey source allows eared grebes to substantially increase their body mass before migrating south. When eared grebes depart from Great Salt Lake, they consistently appear on nearby weather radar as a south-bound column that passes between the mountain ranges south of the lake. We analyzed radial velocity radar data to determine fall departure dates of eared grebes from Great Salt Lake during the migration periods of 1999 to 2013. Previous studies hypothesized that brine shrimp availability or weather may influence the departure of eared grebes. We examined these and other environmental variables that may affect timing of eared grebe departure.