Introduction
The United States Fish and Wildlife Service (USFWS) Recovery Plan for the western snowy plover lists 1.0 chicks fledged per male as a key recovery metric that each recovery unit (RU) must maintain for five years prior to delisting (USFWS 2007). Consequently, researchers in each RU attempt to calculate and report their chicks fledged per male numbers each year. However, in recent years, plover biologists have begun questioning the quality of chicks fledged per male as a statistic. Some longtime researchers, have shifted away from calculating chicks fledged per male and begun using a different metric, breeding efficiency (Colwell et al. 2018). This value is easier to calculate and reduces the amount of uncertainty associated with the necessary variables.
However, other researchers argue that chicks fledged per male is a more accurate reflection of snowy plover productivity, despite its issues. The Snowy Plover Recovery Lead Biologist for USFWS, Micah Ashford (RU2), has shown interest in breeding efficiency and suggested that all RUs calculate both their breeding efficiency and chicks fledged per male for the 2025 season.
This is an evolving debate that should eventually result in a standardized methodology across all RUs for the most accurate and precise snowy plover productivity estimate. However, as of the 2025 season, different researchers use a wide variety of methods to calculate chicks fledged per male and breeding efficiency. Therefore, SFBBO has decided to calculate these metrics using several different methods in an effort to make our data more comparable, and demonstrate how differences in methodology change the outcome of the calculation.