An integrated population model for bird monitoring in North America: Fid-Bau Portal

An integrated population model for bird monitoring in North America

Ahrestani, Farshid S. / Saracco, James F. / Sauer, John R. / Pardieck, Keith L. / Royle, J. Andrew

AbstractIntegrated population models (IPMs) provide a unified framework for simultaneously analyzing data sets of different types to estimate vital rates, population size, and dynamics; assess contributions of demographic parameters to population changes; and assess population viability. Strengths of anIPMinclude the ability to estimate latent parameters and improve the precision of parameter estimates. We present a hierarchicalIPMthat combines two broad‐scale avian monitoring data sets: count data from the North American Breeding Bird Survey (BBS) and capture–recapture data from the Monitoring Avian Productivity and Survivorship (MAPS) program. These data sets are characterized by large numbers of sample sites and observers, factors capable of inducing error in the sampling and observation processes. TheIPMintegrates the data sets by modeling the population abundance as a first‐order autoregressive function of the previous year's population abundance and vital rates.BBScounts were modeled as a log‐linear function of the annual index of population abundance, observation effects (observer identity and first survey year), and overdispersion. Vital rates modeled included adult apparent survival, estimated from a transient Cormack‐Jolly‐Seber model usingMAPSdata, and recruitment (surviving hatched birds from the previous season + dispersing adults) estimated as a latent parameter. An assessment of theIPMdemonstrated it could recover true parameter values from 200 simulated data sets. TheIPMwas applied to data sets (1992–2008) of two bird species, Gray Catbird (Dumetella carolinensis) and Wood Thrush (Hylocichla mustelina) in the New England/Mid‐Atlantic coastal Bird Conservation Region of theUnited States. The Gray Catbird population was relatively stable (trend +0.4% per yr), while the Wood Thrush population nearly halved (trend −4.5% per yr) over the 17‐yr study period.IPMestimates of population growth rates, adult survival, and detection and residency probabilities were similar and as precise as estimates from the stand‐aloneBBSandCJSmodels. A benefit of using theIPMwas its ability to estimate the latent recruitment parameter. Annual growth rates for both species correlated more with recruitment than survival, and the relationship for Wood Thrush was stronger than for Gray Catbird. TheIPM's unified modeling framework facilitates integration of these important data sets.