The sight of the first longtail is always an exciting time of year for Bermudians as they are the first indication that summer is coming. Their distinctive calls, which earned them the nickname “bosun bird” among sailors due to its likeness to a bosun’s whistle, punctuate the sounds of tourists filling our beaches once more. At the moment, Bermuda is at the start of longtail nesting season, and if you pop your head into a crevice in a coastal cliff, you are more than likely to spot a chick!

The yellow billed white tailed tropic bird, (Phaethon lepturus catesbyi), or as Bermudians colloquially know it, the longtail, nests from April to October. These seafaring birds do not construct nests from leaves and sticks, but rather use crevices in cliff faces to house their young. The longtail is a native species that traverses huge stretches of ocean each day to hunt in the open ocean. Laying only a single egg and being threatened by habitat destruction, competition, and predation, the number of nesting pairs of longtails in Bermuda declined after about 1978.

P5050015.JPG
A longtail in a nesting crevice at Horseshoe Bay

Bermuda houses about a half of the global longtail population, with the Caribbean housing the other half of the subspecies of Phaethon lepturus. As such, Bermuda is an extremely important nesting site for the birds. This is lucky for the longtail due to our history of prudent conservation initiatives, and they are protected under the Protection of Birds Act. Their nesting period is the only time longtails spend extended amounts of time on land, instead spending most of their time on the wing in the open ocean, hunting for squid and fish.

The flaky limestone cliffs on Bermuda’s coastline are where longtails search for nesting sites; however, erosion from weathering, hurricanes, and coastal development decreases the number of suitable caves available. In addition, introduced predators, such as dogs, cats, rats and crows, pose a threat to defenseless longtail chicks. Lastly, pigeons, which are often seen as a city bird, actually favor nesting in sea cliffs, and so compete with longtails for nesting sites.

P5050029.jpg
A longtail in a natural nest

The Bermuda Audubon Society, helped by Dr. David Wingate (who was the driving force behind Cahow [Pterodroma cahow] conservation on the island), developed “longtail igloos” in 1997, and as a result of the installation of the artificial nesting sites, longtail numbers have skyrocketed. These styrofoam domes can be cemented to rocky coasts to provide suitable nesting cavities for longtails, and a number have been installed on Nonsuch Island, in the Castle Harbor area, and at Devonshire Bay. As most cliff face nesting sites are easy to reach with a little climbing, the development of longtails from egg to chick to adult can be observed by the determined individual.

Beginning as a purplish-red egg, chicks hatch into small and highly downy versions of their parents. Longtails incubate their eggs until they hatch, and parents take turns keeping the egg warm. Young longtails take 65 days to fledge, and are left alone in the nest for long periods as parents fly far offshore to search for food, which is subsequently regurgitated for the chick.

conservation20longtails202
A young longtail chick in an artificial nesting site – a longtail igloo (audubon.bm)

Longtails are a fascinating species as they are a good example of an animal that is totally adapted to its environment. They are the epitome of a seabird, spending time flying over large stretches of open ocean to hunt. In addition, searing for nesting sites and courtship displays also take place in the air. When not flying, they can be seen floating on the surface of the water or among seagrass beds – they are able to sleep floating in calm waters, or on the wing. On land, their underdeveloped legs don’t allow them to walk properly, an evolutionary characteristic developed from spending so much time in the air. However, this means that longtail chicks that leave the nest too early are very vulnerable, as they are unable to fly, or to use their legs to climb back into the nest.

When food is scarce, due to overfishing of the world’s oceans, some longtail parents encourage chicks out of the nest prematurely. They are too weak to fly, and many are doomed to drown or starve. At the Bermuda Aquarium Museum and Zoo, we receive a few young longtails per year that individuals from the public have picked up. They are fed and cared for until they are strong enough to fly, and then released back out into the wild.

P5050018.jpg
A dead longtail chick that likely fell from a nest

Things that you can do to help longtail populations to continue to grow include:

  • ensuring pets do not gain entrance to longtail nesting sites and kill longtail chicks
  • reporting longtails you see that are injured or cannot fly to BAMZ
  • installing longtail igloos near your home
  • volunteering for BAMZ or the Audubon society to install igloos at public locations, or studying bird populations

In addition, longtail chicks can be observed in nesting sites all over Horseshoe Bay (all the photos besides the young chick were taken by me there), Warwick Long Bay, Devonshire Bay and Castle Harbor, and are interesting to find as long as you don’t disturb the birds!

 

 

Advertisements