Volume 50, No. 1

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Infanticide in highly urbanized colonies of Black Skimmers Rynchops niger




FORYS, E.A., BERES, S.K., MCKAY, A.L. & SPICER, O.N. 2022. Infanticide in highly urbanized colonies of Black Skimmers Rynchops niger. Marine Ornithology 50: 43 - 47

Received 16 August 2021, accepted 15 October 2021

Date Published: 2022/04/15
Date Online: 2022/02/10
Key words: Black Skimmer, coastal ecosystems, disturbance, Florida, Gulf of Mexico, infanticide, urban ecology


Infanticide, which is the killing of dependent offspring, occurs in many species of colonial seabirds. Most infanticide attempts are made when chicks wander outside their parents' territories and are more likely to occur when the colony experiences a disturbance or food is limited. Our objective was to determine the rate of infanticide at three Black Skimmer Rynchops niger colonies located on highly urbanized beaches in Pinellas County, Florida, USA. Infanticide occurred 42 times during 3223 hours of monitoring (0.013 attempts per hour) over four breeding seasons (2018-2021). More than one third of the infanticide attempts occurred after a disturbance, and most of the attackers were not the chick's parents. However, in 10 attempts, parents were observed killing or attempting to kill their own chicks, and these attacks were primarily at a colony experiencing high stress due to coyote Canis latrans predation. We recommend reducing disturbance through a robust bird stewardship program and targeted predator management to reduce infanticide at Black Skimmer colonies in human-dominated ecosystems.


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