by Zoe Diaz-Martin, Intern USF&WS
Thursday, August 1, 2013
The 2013 field season on Falkner is quickly and quietly coming to an end. Overall we had nearly 90 common tern chicks that were monitored in our productivity plots and, as of now, only one is left in the plots. The rest of the common tern chicks have fledged meaning that they are at the stage of life where they have developed flight feathers and wing muscles to begin flying from the nest site. The overwhelming majority of common tern chicks on Falkner are fledglings and so there are very few young chicks remaining.
This season we have had 16 roseate terns fledge successfully and we have only two chicks still at nest sites. Most of our roseate fledglings have left Falkner Island to spend some time in Massachusetts around the shores of Cape Cod. There they will begin the staging period, where they gorge on fish in order to increase their fat reserves, to prepare for their long migration south. They typically begin migrating south in late August or early September. Some of our roseate terns have migrated from as far as Brazil, which is quite impressive. Common terns also complete this staging period and many of our common terns have also left Falkner to begin that process. With the number of birds dwindling, the island has become significantly quieter and the birds calmer.
The Falkner crew only has about two weeks left on island until the field station is packed and boarded up. Overall, it has been a very exciting and productive field season that entailed a lot of data collection and hard work. There are a lot of really cool things about working on the SBMNWR Falkner crew for a summer. For me one of the coolest parts of this internship has been having the opportunity to watch the birds grow as the months have passed. We started the summer seeing the island covered with small speckled eggs and from there we’ve watched the chicks hatch and go through the different growth stages until fledging. In many ways their development has reminded me of how we as humans grow and make our way through this world.
When the common tern chicks first hatch they look like most newborn animals, wet, small, and kind of weird. It sometimes takes the chicks a while to break out from their eggs, which is something you can occasionally see and watch, so when they finally make it out they are very tired. They are tiny little things weighing less than 13 grams and they fit perfectly in the palm of your hand. After a day or two the chicks dry out and become a yellow, brown and white dotted ball of fluff. They are still very small and they spend a lot of time resting so they are not yet very mobile. Their tiny wings are not like wings at all but seem like little stubby appendages flopping at their sides. Soon, however, the chicks get more energy and begin to grow. They still look like balls of fluff but they wander close to their nest site crying out for food and I think of this as the toddler stage of life. In my opinion this is the cutest time for the chicks as they often run around squawking, with their little squat wings flailing around. This is also the age where they often get fish brought to them that are too big to eat (terns gulp down fish in one go), so you can sometimes see these young chicks trying their best to guzzle down a fish only to have it hang half way out of their mouths.
They keep growing as they eat more fish and before you know it they reach their big kid stage where they are much bigger and much less fluffy. Then they hit that oh-so-awkward pre-teen stage. Here they experience a pre-juvenal molt where they loose their down and their feathers come in. Their wings also go through development and their little stubs begin to turn into wings that seem too big for the birds’ bodies. The birds also begin their preformative molt where their flight feathers begin to grown in. Next they
enter the teenager stage of life. They start to experiment with flying, they bully each other and steal each other’s fish. They have dark eye stripes that come in and their feathers become patterned, uniform and sleek. Finally, once they have grown enough, they fledge. In my mind the human equivalent to fledglings are recent high school graduates; they are still reliant on their parents but independent enough to go out on their own and explore a little.
Soon they are all going to head off to begin their staging period, which I think of as college. There they expand their bodies like we expand our minds before beginning their trek south, which is like our journey into the post-graduation ‘real world.’ They will remain young adults for the next three years until they begin breeding themselves. If they make it in this tough world, many of the chicks we watched grow this season will return to Falkner as adults to have eggs of their own. They will continue to entertain the Falkner crew leading them to make funny comparisons between humans and terns and, above all, show them the beauty in living and growing.