When the sparrow’s nest flooded at high tide on the Georgia coast, fish jumped at the chance to make a meal for a newly hatched chick, and a scientist’s video camera captured the first view of the entire deadly encounter.
The footage showed a small fish called a mummichog (Fundulus heteroclitus) Dive into the flooded nest and attack the hatched seaside sparrow (Ammospiza maritima), Showing that baby sparrows in this habitat face a threat previously unknown to scientists.
Corina Newsome, an ornithologist at the Hunter Lab at Georgia Southern University in Stateboro, installed a camera in the bird’s nest to learn about the risks posed by predators. In this case, the predator came from an unexpected place: water.
“After seeing it, a lot of questions came to my mind,” Newsom told Live Science.
Georgia’s tidal marshes are home to many species of birds, and the seaside sparrows that live there are known to nest in flood-prone areas when the tide is high. Reported on February 5th, her co-author. Wilson Journal of Ornithology.. Studies show that this can be dangerous for young chicks, but they often withstand small floods.
However, choosing a higher, drier nesting site increases the likelihood that freshly hatched turtles will be exposed to many predators, Newsam said. Large birds such as crows and gracles, like raccoons, marsh rice rats, and American minks, taste baby sparrows. Sparrow chicks tend to be safer in nests near the ground because they provide a protective cover.
Durable mummichogs also live in salt marshes. These fish can be up to 3 inches (9 centimeters) in length and are highly resistant to adverse conditions such as low levels of oxygen and dramatic temperature changes, and a variety of small aquatic animals such as snails, clams and other fish. Eat animals. The researchers wrote in the study.
Threat from below
On June 5, 2019, one of Newsome’s cameras recorded anomalous activity in a sparrow’s nest flooded at high tide. The nest contained two eggs and a chick that hatched earlier that day.
“In the video, you can see the water gradually rising in the nest and the chicks floating above the water,” Newsom said. Suddenly, a fish jumps out of the edge of the nest and takes a short break next to a floating turtle that has just hatched — and it attacks. Studies show that mummichog pulls chicks into the water and “slaps them in their mouths” until the cuddly drowns.
The flooded nest is not necessarily an automatic death sentence for sparrows. Even a newly hatched baby bird can withstand a dunk if it can keep its head above the water and sink before it cools too much.
“But if predators access their nests with water, it presents a whole new threat,” Newsom said. This was not previously reported by scientists, she added.
The encounter may have filled Mummichog’s belly, but it has made researchers crave for answers to previously unseen dangers. For example, Newsom asked how the threat of nest predation differs between aquatic and terrestrial predators. Sparrows nest to optimize protection against one type of predator, but will they eventually become more vulnerable to other predators? And are fish the only aquatic carnivores that take advantage of flooded nests, or do black marsh turtles snack on freshly hatched turtles at high tide?
“Many studies have been done to show that as the height of the nest above the ground increases, the predation of the nest increases,” Newsum explained. “But this adds a layer of complexity to what the predatory threat actually looks like to this species.”
Originally published in Live Science.
The video captures the unusual death of a baby bird drowning in a fish
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