Along U.S. Atlantic and Gulf Coast barrier islands, red foxes (Vulpes vulpes) are top predators that are thought to impact smaller mesopredators and depredate beach-nesting birds. Starting in 2015, sarcoptic mange epizootics among red foxes led to their eventual temporary extirpation from most of Fire Island, NY, USA. We monitored the subsequent changes to the mammalian predator community on this barrier island and explored the impacts to piping plovers (Charadrius melodus), a federally threatened shorebird. We deployed trail cameras and quantified detection rates of four common shorebird predators (red foxes, northern raccoons Procyon lotor, Virginia opossums Didelphis virginiana, and invasive domestic cats Felis catus), and tested for effects of predator activity and density on piping plover nest and brood survival. Following the loss of red foxes, northern raccoon and Virginia opossum activity remained relatively unchanged, while cat activity increased. The cat population grew from 14 to 42 individuals across the three study areas, and cats later became the most frequently detected mammalian predator. The loss of red foxes was associated with increased plover nest survival (β ± SD = 1.08 ± 0.55), though the increase of cats in later years was associated with a strong, negative decline in nest survival (β ± SD = −3.08 ± 1.28). Plover brood interval survival was negatively correlated with cat density (β ± SD = −0.50 ± 0.14) but not with red foxes. We underscore the importance of monitoring invasive predators during periods of trophic downgrading, which may have delayed impacts to native fauna.

Wails, C. N., K. M. Black, S. M. Karpanty, H. A. Bellman, A. DeRose-Wilson, S. S. Dorsey, K. W. Oliver, S. J. Ritter, S. G. Robinson, H. L. VanDerwater, D. H. Catlin, and J. D. Fraser. 2025. Responses of a federally threatened shorebird to trophic downgrading and expansion of domestic cats (Felis catus). Biological Invasions 27:78. doi: 10.1007/s10530-025-03544-1

The use of unique markers in ornithology has a long history and is predicated on the assumption that markers have negligible effects on behavior and survival. The assumption that marks are harmless is particularly important with imperiled species. We studied the effects of two different marking schemes on Piping Plovers (Charadrius melodus), a small shorebird protected under the U.S. Endangered Species Act that is intensively monitored and managed. We used two marking schemes, (1) color bands and (2) uniquely engraved flags during breeding seasons from 2013 to 2023 to determine whether the injuries were causing additive mortality and thus actually limiting populations. We estimated the effect of perceived limping and injury (e.g., swelling, laceration, etc.) on chick and hatch-year survival. We detected injuries in some years and associated with both marking schemes (range 0.0–6.0%, average = 2.7% of marked chicks each year). Interval survival for banded chicks was like that of flagged chicks (β= − 0.55, 95% BCI: − 1.30–0.33, f = 0.92). Mean survival to fledging, however, was higher in years where flags were used (ɸ = 0.55 ± 0.14) than when bands were used (ɸ = 0.34 ± 0.14), but we surmise that this difference was partly conflated with negative density-dependent factors (β = − 0.49, 95% BCI: − 0.73 to − 0.25, f = 1.00) and predation. Our results show that pre-fledge survival of birds with uniquely coded flags was similar to that of birds receiving color bands. There was also no evidence that injured birds had a significantly lower hatch-year survival than those that were not injured. However, the relatively high (up to 6%) injury rate in some years remains a concern. Injury and survival rates need to be considered and evaluated when deciding on whether to mark individuals. Ultimately, wildlife practitioners should strive to use the best methods for information gathering and management, without negatively impacting the species.

Wails, C. N., D. H. Catlin, S. G. Robinson, H. A. Bellman, K. W. Oliver, H. L. VanDerwater, S. S. Dorsey, A. DeRose-Wilson, S. M. Karpanty, and J. D. Fraser. 2024. Comparing the effects of marking techniques on the survival of Piping Plover chicks. Journal of Ornithology 166:275-283. doi: 10.1007/s10336-024-02211-x