Every time when I go out for birding, I’m always interested in seeing birds that I haven’t seen previously, or “lifers” in birding terminology. However, there is something that fascinates me even more: behaviors. Birds display all kinds of behaviors related to foraging, mating, antipredation, and more… Many of these behaviors vary temporally and spatially. For example, some migratory birds that forage high up in the canopy during the breeding season shift to understory foraging on their wintering grounds. Additionally, behaviors can vary in different social contexts, which include the presence/absence of their social partners. Today, let’s chat about one rare and understudied bird behavior, interspecific allopreening.
WHAT DOES ALLOPREENING MEAN?
In Latin, the root allo- means other. As preening refers to the movement when one bird tidies its feathers with its bill, and allopreening refers to the behavior when one bird uses its bill to tidy the feathers of another bird. I’m sure some of you have seen this behavior between different individuals of the same species (within-species allopreening). For example, perhaps you have seen a pair of Mourning Doves preen each other after a courtship display? Or maybe you have seen your pet parrots preen on each other? While within-species allopreening is common, interspecific allopreening is much rarer.
SO, IN WHICH SPECIES PAIRS HAVE THE INTERSPECIFIC ALLOPREENING BEHAVIOR BEEN RECORDED?
In natural environments, there are few documented records. First and most notably, interspecific allopreening has been reported multiple times at multiple locations in the New World between Black Vultures and Crested Caracaras. Also in the New World, interspecific allopreening has been recorded between Razorbills and Common Murres in Canada. In the Old World, this behavior has been observed between a Royal Spoonbill and an Australia White Ibis in Australia, a Sacred Ibis and an African Spoonbill in Africa, and two Parakeets in Europe.
Apart from these records, some species in the Blackbird family, such as the Brown-headed Cowbird, are known to actively seek interspecific allopreening from other species by performing allopreening invitation displays. They oftentimes approach other species and gradually lower their heads (head-down display) to allow other species to preen their head and neck areas.
WHY DO YOU THINK THIS MYSTERIOUS BEHAVIOR OCCURS?
Unfortunately, we don’t really have an answer. Because events of interspecific allopreening are rare, few researchers so far have been able to collect enough data to effectively demonstrate the reasons behind this behavior. Most studies related to interspecific allopreening are based on anecdotes.
If you want to learn more about interspecific allopreening behavior, check out this short article that has recently been published in the journal Ecology and Evolution. The authors observed this behavior between two babbler species in Asia and proposed several hypotheses. They also suggested locations and species in which interspecific allopreening is more likely to be observed.