Bird Rescue is proud to announce the publication of an important scientific paper on a rescue-and-rehabilitation effort that led to a notable success: the post-release survival and breeding of a group of Caspian Terns in Southern California. The paper was authored by Bird Rescue’s Julie Skoglund with assistance from Rebecca Duerr, DVM MPVM PhD.
The story began in 2006 and 2007 in the Port of Long Beach, one of the busiest shipping ports on the west coast and near a favored breeding colony locale for both Caspian and Elegant Terns in southern California. In both years, disastrous events threatened the lives of tern chicks born in the Port of Long Beach.
In 2006, workers cleaning the deck of a barge deliberately flushed Caspian Tern chicks—too young to survive independently—into the Pacific Ocean. In 2007, suspected human disturbances caused another group of tern chicks to wind up floundering in the water. Fortunately, Bird Rescue was able to rescue some of these young birds and take them into care at its Los Angeles Wildlife Center.
The fact that these chicks were able to survive and breed after release is especially noteworthy because terns pose unique challenges for rehabilitators. Adult terns typically nest in colonies and are plunge-divers, which means they raise their young communally and they hunt by hovering over the water in flight, spotting fish below the surface, and then plunging into the water to catch their prey. Becoming effective at feeding in this fashion requires training and practice, so young terns spend many months flying with and being guided and supplementally fed by their parents to master this skill well enough to survive on their own. Unfortunately, this type of learning is pretty much impossible to replicate in captivity. Conservation efforts that work well with other species of birds, such as captive rearing for wild release, are not suitable for terns. And the situation is made more desperate by the fact that critically endangered tern species population numbers continue to drop: tern colonies remain vulnerable to environmental disasters and human disturbances that disrupt breeding for an entire colony, or kill all of its young of the year at once.
Bird Rescue pioneered a unique, “natural” method for turning the rescued chicks into capable, self-sufficient adult terns. The fact that some of the rescued chicks have been seen as adults, alive and in breeding colonies years later, is a strong sign of the effort’s success. With Bird Rescue’s care and help, these chicks overcame their traumatic early life. These very young birds learned to fend for themselves and survive, and were able to breed successfully as adults. This validates the care regimen at Bird Rescue and gives us hope for future populations.
As rehabilitators, we feel proud knowing that our extensive rehabilitation efforts were a success. We also want to acknowledge the expert collaborative help we received from ornithologist Dr. Charlie Collins, Professor Emeritus at California State University of Long Beach.
To understand how we solved the challenges of rehabilitating these terns, please read Survival and Recruitment of Rehabilitated Caspian Terns in Southern California.
The final paper was published in the Bulletin of the Southern California Academy of Sciences, May 2020.