Bird houses have been around for centuries. They have been built since Turkey’s Pre-Ottoman Empire, and even today they are commonly found in backyards, whether it is to attract birds or for decoration purposes. But who knew that these bird houses could be the answer to saving highly endangered seabirds?
Due to the impacts of urbanization and the introduction of mammalian predators specifically on islands, seabirds are one of the most threatened animal taxa. Today, many Mediterranean Storm Petrels, a small, pelagic seabird species, are confined to islands, where they are locally endangered due to the overabundance of predatory gulls, specifically the Yellow-legged Gull. The gulls are harmful not only to the adult Storm Petrels but also to their eggs, and ultimately, their decreasing population is a significant threat to the once rich biodiversity of island birds.
Realizing the dire need for conservation efforts in order to save these seabirds, Emmy Libois and her colleagues of the Biostatistics and Population Biology Group in Montellier, France proposed providing nesting habitats for the Storm Petrels. The study was conducted from 1993 to 2010 in the Special Protection Area for the conservation of the Storm Petrel in the Mediterranean coast of Spain, also known as the Benidorm Island. This location was ideal for this study because it had two caves that had hundreds of breeding Storm Petrels that lived under the caves’ boulders and in crevices; as Storm Petrels are endangered species, it is very rare to find natural habitats occupied by hundreds of Storm Petrels.
So how did Libois and her colleagues keep track of these endangered Storm Petrels and their eggs that are so vulnerable to damage and consumption by their predators? First, breeding adult Storm Petrels were captured in their nests and marked with stainless steel bands, once every breeding season since 1993. Every nest was then monitored by weekly visits during the breeding period, and researchers estimated the proportion of chicks fledged in relation to the number of eggs laid; chicks were considered to fledge if they were at least 35 days old.
The results of this study showed that nest box installations are a milestone in the process of saving the endangered Storm Petrel population. Just several years after installing nest boxes in Benidorm Island, the higher survival rates and breeding success probabilities for Storm Petrels that bred in the artificial nest boxes instead of natural breeding sites were significantly higher. They also found that the majority of Storm Petrels that settled in the artificial nest boxes were prospective, first-time breeders. Breeders that were older and had more experience were found more often in their natural habitats. The higher breeding success rate of the breeders that bred in the artificial nest boxes tells researchers that the success may be due to the nesting boxes’ habitat features. Researchers also attribute this success to the fact that nest boxes provide a safe habitat that the predatory gulls do not have access to.
This study demonstrates how a simple habitat installation can have significant impacts in rescuing endangered species. However, this study is more than just a happy story of conservation success. While nest boxes are highly beneficial for protecting endangered species from its predators, artificial nest boxes pose new problems and threats as well. If more Storm Petrels, especially ones that are breeding, prefer the artificial nest boxes to their natural habitats, birds in the nest boxes may face density-dependent problems, such as food limitation or spread of infectious diseases. Furthermore, it may attract more of its predators’ attention simply due to its big population.
While the issue regarding endangered species is a serious issue that many assume require urgent attention and a large-scale project to restore the population, it clearly isn’t the case. Something as simple as a nest box made out of pieces of plywood can rescue endangered bird species. So what does this mean? This comes to show just how much impact, whether it is for the better or for worse, that humans have on the environment, the fragile balance of different species, and ultimately the biodiversity of our nature. And hopefully, with the right ways of intervention and rescue efforts, we will be able to see once endangered species showing an upward trend in their population.
Source article: Libois, E., et al. (2012). Nest boxes: A successful management tool for the conservation of an endangered seabird. Biological Conservation, 155, 39-43.
Source picture: http://en.wikipedia.org/wiki/File:MSP01b.jpg