Combining waterfowl and breeding bird survey data to estimate wood duck breeding population size in the Atlantic Flyway

Abstract

We combined data from the Atlantic Flyway Breeding Waterfowl Survey (AFBWS) and the North American Breeding Bird Survey (BBS) to estimate the number of wood ducks (Aix sponsa) in the United States portion of the Atlantic Flyway from 1993 to 2013. The AFBWS is a plot-based survey that covers most of the northern and central portions of the Flyway; when analyzed with adjustments for survey time of day effects, these data can be used to estimate population size. The BBS provides an index of wood duck abundance along roadside routes. Although factors influencing change in BBS counts over time can be controlled in BBS analysis, BBS indices alone cannot be used to derive population size estimates. We used AFBWS data to scale BBS indices for Bird Conservation Regions (BCR), basing the scaling factors on the ratio of estimated AFBWS population sizes to regional BBS indices for portions of BCRs that were common to both surveys. We summed scaled BBS results for portions of the Flyway not covered by the AFBWS with AFBWS population estimates to estimate a mean yearly total of 1,295,875 (mean 95% CI: 1,013,940-1,727,922) wood ducks. Scaling factors varied among BCRs from 16.7 to 148.0; the mean scaling factor was 68.9 (mean 95% CI: 53.5-90.9). Flyway-wide, population estimates from the combined analysis were consistent with alternative estimates derived from harvest data, and also provide population estimates within states and BCRs. We recommend their use in harvest and habitat management within the Atlantic Flyway. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

Using the North American Breeding Bird Survey to assess broad-scale response of the continent's most imperiled avian community, grassland birds, to weather variability

“…Focusing on a temporal pattern, the modeled pattern of variation in this index is referred to as the population trajectory. In combination with population size surveys, BBS trajectories can be used to predict population sizes from areas of overlap and areas covered only by BBS data (Runge et al 2009, Millsap et al 2013, Zimmerman et al 2015.…”

Survival, Harvest, and Lincoln Estimates of Wood Ducks Banded in Ohio

“…We found males had slightly higher harvest rates than females, and although not statistically significant, adult males and adult females had slightly lower harvest rates than their hatch-year counterparts as we hypothesized and other published studies have found (Johnson et al 1986). Zimmerman et al (2015) combined data from the Atlantic Flyway Breeding Waterfowl Survey and North American Breeding Bird Survey and estimated approximately 1.3 million wood ducks for the U.S. portion of the Atlantic Flyway. We are unaware of any other Lincoln estimates using harvest data for wood ducks other than Zimmerman et al (2015) and Bowers and Martin (1975), but considering continental spring breeding population estimates for several other common waterfowl species including mallards Anas platyrhynchos and blue-winged teal Anas discors reach well into the millions, state-wide estimates of several hundred thousand wood ducks seem plausible.…”

Multi‐species duck harvesting using dynamic programming and multi‐criteria decision analysis

“…We used population size estimates during 1998-2017 from the eastern portion of the Waterfowl Breeding Population and Habitat Survey (WBPHS; Zimmerman, Sauer, Link, & Otto, 2012) (Zimmerman, Sauer, Fleming, Link, & Garrettson, 2015). At the time of our assessment, we had BBS data through 2015, so the available time series for wood duck breeding population estimates was limited to 1998-2015.…”