Animals like raccoons and opossums prey on the young of birds with nests in the Everglades but some birds eventually developed a strategy to keep their nests safe from these bandits.
Findings of a new study have revealed that birds like herons, ibises, egrets and storks have learned that alligators can scare away most intruders if they strategically place their nests above where these gators hangout.
The alligators, being the fearsome predators that they are, act as these birds' body guards but the protection they provide comes at a prize: the reptiles would eat the eggs and chicks that drop off the birds' nests.
The dropped chicks are actually those that are ejected from the nest when a bird lays more eggs than it is capable to feed. Some birds produce more chicks than they can care for and pushing out these surplus chicks to be eaten by the alligator can be viewed as a beneficial alternative to starving them.
"Our study is the first to demonstrate a mutually beneficial relationship between nesting birds and a crocodilian: nesting wading birds provide nutrition for alligators that, by their mere presence, create predator-free space for birds," said study researcher Lucas Nell, from the University of Florida.
The research, which was published in the journal PLOS ONE, also established how the relationship proves to be beneficial to the alligators.
How bird species benefit from living near alligators are well documented but there are only a few studies that looked at the effect of the relationship on the protector.
For the study, Nell and his colleagues compared the body weight and general condition of the alligators that thrive under the bird nests with those of gators located far from nesting colonies.
They found that the body condition of alligators that live near the nesting colonies of birds was far better than those of alligators in similar habitats where there are no active bird colonies.
Although the nests are placed high enough to prevent the alligators from getting to them, the eggs and chicks that fall were plenty enough to have noticeable impact on the diet of the alligators.
"These findings suggest the interaction is highly beneficial for both groups of actors, and illustrate how selective pressures may have acted to form and reinforce a strongly positive ecological interaction," the researchers wrote in their study.
