Age‐specific survival and recruitment of piping ploversCharadrius melodusin the Great Lakes region

Abstract

Juvenile survival and age at first breeding (i.e. recruitment) are critical parameters affecting population dynamics in birds, but high levels of natal dispersal preclude measurement of these variables in most species. We used multi‐state capture–recapture models to measure age‐specific survival and recruitment probabilities of piping plovers Charadrius melodus in the Great Lakes region during 1993–2012. This federally endangered population is thoroughly monitored throughout its entire breeding range, minimizing concerns that measures of survival and recruitment are confounded by temporary or permanent emigration. First‐year survival (± SE) averaged 0.284 ± 0.019 from mean banding age (9 d) and 0.374 ± 0.023 from fledging age (23 d). Factors that increased first‐year survival during the pre‐fledging period (9–23 d) included earlier hatching dates, older age at banding, greater number of fledglings at a given site, and better body condition at time of banding. However, when chicks that died prior to fledging were excluded from analysis, only earlier hatching dates improved first‐year survival estimates. Females had a higher probability (0.557 ± 0.066) of initiating breeding at age one than did males (0.353 ± 0.052), but virtually all plovers began breeding by age three. Adult survival was reduced by increased hurricane activity on the southeast U.S. Atlantic coast where Great Lakes piping plovers winter and by higher populations of merlins Falco columbarius. Mean annual adult survival declined from 1993 to 2012, and did not differ between males and females. Enhanced body condition led to higher survival to fledge and early breeding led to improved first‐year survival; therefore, management actions focused on ensuring access to quality feeding habitat for growing young and protecting early nests may increase recruitment in this federally endangered population.

Direct and indirect effects of nesting density on survival and breeding propensity of an endangered shorebird

“…There are examples of a mismatch between the expectation based on estimated reproductive output and the reality of population growth for piping plovers (Hecht and Melvin 2009). In a study of Great Lakes plovers that did control for imperfect detection, Saunders et al (2014) found that 35% of male birds breed in their first year and 56% of females do, which is comparable to the rates for males we noted in our study but was still far lower for females. Similarly, detection can affect estimates of first-year breeding propensity.…”

Evaluating population viability and efficacy of conservation management using integrated population models

“…Every 1–4 days, monitoring teams recorded nesting activities of colour‐banded adults (Brudney, Arnold, Saunders, & Cuthbert, ), including locations of nests, counts and fates of eggs, hatch dates and number of chicks that survived to fledging age ( c . 23 days old; Saunders, Arnold, Roche, & Cuthbert, ). We used the total number of fledglings observed each year, in conjunction with the number of surveyed broods, as productivity data.…”

“…Previous work demonstrated that adult plover survival in the Great Lakes region has been negatively associated with annual abundance of eastern North American merlins (Saunders et al., ), and disappearances of breeding adults are most frequently attributed to predation by merlins (Roche, Arnold, & Cuthbert, ). We obtained raw annual counts of merlins migrating through Hawk Mountain in Pennsylvania during autumn (August–December) and through Whitefish Point in Michigan during spring (March–May) throughout the 24‐year study period (http://www.hawkcount.org).…”

Can river management improve the piping plover’s long-term survival on the Missouri River?

“…obs.). Most plovers breed by age three, and 35-56% breed by age one (Saunders et al, 2014). Females lay eggs in a small depression in the sand, often lined with shells or pebbles, within their mate's territory.…”