The Leach’s storm petrel is a seabird that number in the millions but is rarely observed. These birds are pelagic, meaning that they spend most of their lives in the open ocean, often traveling great distances to locate food. This is a surprising feat considering they are small for a seabird (about 1.5 feet wingspan). They only come ashore during the summer to lay and care for a single egg in an underground burrow.
Interestingly, most storm petrels only nest on isolated offshore islands without many natural predators. To make them even more difficult to see, they only enter and leave their burrow during the darkest hours of twilight, sometimes staying in the burrow days on end. This is yet another way to avoid predation from predators such as gulls that could pick off storm-petrels.
Last summer, I worked with seabirds on a remote island off the coast of Alaska. The research focused mainly on nesting kittiwakes, gulls, and puffin species. However, we also attempted to locate potential Leach’s storm petrel colonies, which although suspected, have yet to be affirmed. Due to their peculiar nesting habits, this was much easier said than done.
The island is lined with cliffs that were either steep and unascendable or covered in thickets of vegetation. The vegetation consisted of thorny salmonberries or noxious hogweed, which is harmful when touched to the skin. The lowlands below the cliffs were often home to marshes that appear shallow with a mossy vegetative cover. However, when stepped on, one could sink in several feet or further.
Our first strategy to locate these birds involved placing stationary audio recorders. After finding no concrete evidence on our first set of recorders, I moved on to walking the cliffs at night to listen for the calls of incoming and outgoing nesters. Due to the increased day length during the Alaskan summer, I only had a small window of opportunity.
After several nights of walking atop the cliffs in the darkness, I finally heard the faint chatter of a storm-petrel just after 2:00 am. Listen to the strange chuckling of a Leach’s Storm Petrel from my recording below:
Leach's Storm Petrel Chuckling
After moving towards the sound, I reached a cliff overlook where I could hear many storm-petrels calling. Their silhouettes were visible circling the cliffs as they flew to and from burrows along the upper portions of the cliff. They squeezed themselves into small holes dug into dirt or sand where their eggs and chicks awaited them. The nesting pair was either switching the duties of egg incubation or bringing back food collected in their bills for young chicks. Not too soon after, the calls began to quiet, and the last storm-petrel ceased calling before 2:30 am.
Incredibly, the site where the storm-petrel colony was found was a place that we regularly pass by during the day. I never would have imagined that a colony of these birds was hiding under our noses the entire time. The inconspicuous nature of this species has allowed them to elude years of field researchers on the island until now.
This is an exemplary example of how this seemingly small and vulnerable group of birds has managed to survive. There could be many more storm-petrel colonies just waiting to be discovered.
