Identifying Juvenile Warblers

The Fun Really Begins Here

The Monitoring Avian Productivity and Survivorship (MAPS) Program is a continent-wide collaborative effort among researchers and citizen scientists to assist the conservation of birds and their habitats through bird banding ( MAPS-banding). Since 1989, more than 1,200 MAPS banding stations, spread across North America, have recorded more than 2 million bird captures. MAPS data enable assessment of avian demographic vital rates such as productivity, recruitment, survival, and intrinsic population growth, and these supplement other monitoring data by providing insights into what factors drive avian population declines. For example, low productivity indicates problems are occurring on breeding grounds whereas low survival suggests problems are occurring on winter grounds or during migration.

MAPS data recently have been used in an important study documenting substantial long-term effects of West Nile virus on survivorship in North American birds (George et al. 2015). Up to seven vital rates from MAPS data, for 158 landbird species within various conservation regions and other areas, are now available online ( and see DeSante et al. 2015). In 2011 the Boreal MAPS Program was initiated in northeastern Alberta to evaluate landbird demographic rates in reclaimed habitats and other habitats subjected to varying levels of disturbance relative to those in natural boreal forests (Foster et al. 2012). Few demographic data on landbirds have been collected in the boreal forest (Wells 2011), making this program an important contributor to understanding bird populations and vital rates from local to continental scales. During July of our first field season we began to catch recently fledged juvenile wood warblers (family Parulidae) in the mist nets. Frankly, we had a very difficult time, at first, with their identification.

Identifying Juvenile Warblers
Peter Pyle,Christine M. Godwin, Kenneth R. Foster

Birding – Vol. 47 No. 6 Nov/Dec 2015

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