Positive correlation between Ammospiza caudacuta (Saltmarsh Sparrow) capture and productivity supports use of a novel rapid assessment monitoring protocol

Abstract

Salt marshes in the northeastern United States provide critical breeding habitat for tidal marsh specialist birds like the Ammospiza caudacuta (Saltmarsh Sparrow). The Ammospiza caudacuta population declined by 9% annually from 1998 to 2012, necessitating immediate conservation actions for this vulnerable species. However, estimating species vital rates across a large geographic region is logistically challenging and cost prohibitive. Therefore, we developed and tested a rapid assessment monitoring protocol focused on reproductive metrics to enhance future conservation planning. We used 3 years (2018, 2019, and 2021) of intensive demographic data from 12 sites to estimate daily nest survival, nest period success, fledglings produced per female, and successful broods per female. We implemented the rapid assessment protocol co-located at intensive sites in the same years to estimate the number of captured females and juveniles. We used Pearson’s correlation analyses to determine the association of intensive metrics with rapid metrics. We found that the sum of Ammospiza caudacuta female and juvenile captures was positively correlated with daily nest survival (r = 0.61, P = 0.01), nest period success (r = 0.70, P = 0.002), fledglings produced per female (r = 0.82, P < 0.001), and successful broods per female (r = 0.82, P < 0.001). Our results demonstrate that fixed-effort mist-netting from our rapid assessment protocol is an informative and time-efficient sampling method that can aid in making informed management decisions related to Ammospiza caudacuta conservation.