A Brutal Day at the Black Skimmer Colony
The overcast, gloomy, and windy conditions foretold a brutal day at the Black Skimmer colony at St. Pete Beach. I arrived at the beach colony a half hour past sunrise, yet it was still mostly dark. Two other photographers and an Audubon bird steward were already there. The wind was howling, sandblasting us and the birds. Conditions were tough and I took a few snaps with the 800mm lens with an attached 1.4x teleconverter at f/9 at very high ISOs. I cleaned up all the images using Topaz Photo AI with varying degrees of success.
Black Skimmer adult and chick hunkering down during a windstorm. Nikon Z9 with tripod-mounted Nikkor Z 800mm f/6.3 lens with attached 1.4x teleconverter at f/9, ISO 5000, 1/2000 sec.
Black Skimmer chick during a wind storm. Nikon Z9 with tripod-mounted Nikkor Z 800mm f/6.3 lens with attached 1.4x teleconverter at f/9, ISO 4000, 1/2000 sec.
Black Skimmer chick, sibling, and a partially buried unhatched egg in the nest. Nikon Z9 with tripod-mounted Nikkor Z 800mm f/6.3 lens with attached 1.4x teleconverter at f/9, ISO 4000, 1/1250 sec.
In addition to the weather, the colony was under constant assault by Laughing Gulls and Fish Crows. The Audubon bird steward told me he saw more than a dozen chicks get picked off by the gulls and crows just the day before.
But that’s not all. Black Skimmer chicks also faced mortal danger from…other Black Skimmers. Sibling rivalry is a matter of life and death in bird nests, and the first born has the distinct advantage of being bigger than its younger siblings. Older chicks attacking their siblings, even to the point of death, is a pretty common sight in bird nests. They are usually the first to eat and get the most food from their parent, putting their siblings at an even greater disadvantage. In the photo above, you can see how big the older chick is compared to its younger sibling who cannot even stand up in the punishing wind. The chick in the egg, if it ever hatches, stands no chance of survival.
Black Skimmer chick attacking its younger and smaller sibling. Nikon Z9 with tripod-mounted Nikkor Z 800mm f/6.3 lens with attached 1.4x teleconverter at f/9, ISO 5000, 1/2000 sec.
If fratricide isn’t bad enough, Black Skimmer chicks also face mortal danger from other Black Skimmer adults. While I was at the colony I was shocked to see wandering chicks get attacked and killed by neighboring Black Skimmer adults. It happened three times in the hour and a half I was there observing, and each time it was incredibly difficult to watch, much less photograph.
Black Skimmer adult attacking a chick. Nikon Z9 with tripod-mounted Nikkor Z 800mm f/6.3 lens with attached 1.4x teleconverter at f/9, ISO 3200, 1/2500 sec.
Black Skimmer adult attacking a chick. Nikon Z9 with tripod-mounted Nikkor Z 800mm f/6.3 lens with attached 1.4x teleconverter at f/9, ISO 3200, 1/2500 sec.
Black Skimmer chick following an attack by an adult. Nikon Z9 with tripod-mounted Nikkor Z 800mm f/6.3 lens with attached 1.4x teleconverter at f/9, ISO 3200, 1/2000 sec.
Why would an adult Black Skimmer attack and kill a chick of its own species? To answer this question, I first turned to birdsoftheworld.org. According to this website, Black Skimmers demonstrate varying levels of aggressiveness depending on the phase of nesting. Aggression is generally high early in the season when they are finding mates, decreasing to a lower level during egg incubation and increasing dramatically during hatching—partly due to chasing intruding terns and skimmers that attempt piracy from chicks (1). Thinking back on when these attacks occurred, they did seem to coincide with attacks from the gulls and crows flying overhead.
Infanticide behavior in skimmers is confirmed by another study which found that when human disturbance caused the adults to flush, “this flushing would spook any chicks in the nesting area, causing them to run frantically. Once the adults return to the ground, any displaced chicks are quickly grabbed and killed by the adults, believing that these chicks are not their own. In intense disturbance situations, adults will go as far to kill their own young in a stress-induced panic (2).”
When these attacks were occurring, one of the photographers asked the bird steward if our presence might be causing this aggressive behavior and if we should back up even further. The steward rightly observed that these attacks were occurring throughout the colony, including areas where no one was nearby. In light of what I’ve learned since that morning, I would conclude the most likely reason for these attacks was not caused by human disturbance, but rather their naturally heightened aggressiveness aggravated by the constant gull and crow attacks.
Understanding these natural behaviors, and how they can be influenced by human disturbance, is critically important in nature photography. With this knowledge I believe future sessions at Black Skimmer colonies will yield even better photos (because I can anticipate this natural behavior) while also helping me to understand the impact of human disturbance on the colony.
Sources:
Gochfeld, M., J. Burger, and K. L. Lefevre (2020). Black Skimmer (Rynchops niger), version 1.0. In Birds of the World (S. M. Billerman, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.blkski.01
Chimelis, A. New Eckerd Study finds Black Skimmer Infanticide Deaths linked to Human Disturbance, The Current. Eckerd College, St. Petersburg, FL, ISA. https://tinyurl.com/5n8r76s6.
