Sable Island Birds:

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Leach's Storm-Petrel

In early July 1994 the nocturnal vocalizations of Leach's Storm-petrels were first heard as one or two birds flew around an isolated building for several hours after midnight. These calls were heard again in June and July of 1995, but it was not until 1996 that the birds were discovered nesting under building foundations, walkways and wood piles on the island. Colonies are now established on Sable Island, and, based on nocturnal vocalizations of birds in flight and in burrows, there may be a hundred or so pairs nesting on the island. The first petrels arrive in the colony as early as March 31st, and the last remain until at least October 3rd.

Leach's Storm-Petrels lay a single creamy white egg in long horizontal burrows which they dig in earth - the males do the digging, mostly using their feet. Since burrows cannot be made in loose sand, on Sable Island, petrels dig into the sand under solid materials and structures, thus their burrows have a secure roof'. Petrels may also use natural holes and crevices. _ 

Gulls

Two gull species regularly nest on Sable Island - Herring Gull and Great Black-backed Gull.  The Herring gull, with a wingspan of 147 cm, is the most commonly seen gull in most coastal areas of Atlantic Canada.  Some overwinter on the island, but the majority of Herring Gulls winter elsewhere and return to Sable in the spring to nest - roughly 1500-2000 breeding pairs converge on the dunes and establish nesting colonies.  Great Black-backed gulls, with a wingspan of 165 cm, are much larger than Herring Gulls.  Although some Black-backs are on Sable year-round, numbers increase during April when about 1000 breeding pairs take up residence on the island.

Black-legged Kittiwakes are seen in all months at Sable Island, standing on the beach or feeding just offshore.  On several occasions, usually in winter and spring, 1000s have been seen during one day, flying and feeding along the north side of the island.  In June 1997 a small nesting colony of kittiwakes was found on a high dune near the east end of the island.  There were 12 nests, all with eggs.

In 1998, five pairs returned to the nesting site, but only one live chick was seen (July 27 and 31); in 1999 five pairs were on nesting platforms during June, but nests were not inspected.  In May 2000, only one pair was present at the colony. Although other factors may have been involved, the poor success of this colony was due largely to the choice of nesting terrain.

Terns

Sable Island is an important breeding area for Common and Arctic Terns, and for a very small number of Roseate Terns.  The number of nesting terns has diminished since the early 1900s when "many tens of thousands" were reported. This decrease may be related, in part, to an increase in the gull population on the island - from just a few at the turn of the century, to thousands of nesting pairs today.  Consequently, terns may be subjected to increasing predation which results in greater egg and chick mortality.  While gulls are considered to be one cause of diminishing populations, other factors are the loss of nesting and wintering habitat, mortality of migrating adults, and reduction of food supplies.  These factors - as well as the increase in the gull populations - are largely the result of human activities.  The importance of Sable Island as a breeding area for terns is in its potential as a conservation area for the birds - an area with a relatively isolated location, with limited accessibility.

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