Those who spend time near the ocean during the summer are familiar with
the distinctive kee-ar-r-r call of a small, mostly white seabird called
a tern. Tern's are remarkable birds. Known locally as "mackerel gulls,"
they can be seen flying gracefully like swallows, diving into the water,
often leaving with a small fish in their bills. They likely spend more
time in the air and more hours in daylight than any other animal. Terns'
oceanic wanderings take them from extreme northern to southern latitudes
which may exceed 35,000 km in a single year! Three species of terns-common,
Arctic, and roseate-now nest in Nova Scotia, and it takes a fair bit
of practice to tell them apart.
Historically, terns nested in abundance along much of the North Atlantic
coast including on the coastal islands around Nova Scotia. Recently,
there has been much concern because of a dramatic decline in both the
number of colonies and the number of pairs of breeding terns in Atlantic
Canada and the northeastern United States. The roseate tern, the least
abundant of the three, has shown the largest decline in recent years.
As a result, the roseate tern has been designated a "Threatened Species"
by the Committee On The Status of Endangered Wildlife In Canada (
COSEWIC).
The only known breeding colony of roseate terns in Nova Scotia is located
on the Brothers Islands, Yarmouth County. Some may know them as the
"Twin Islands."
The Brothers Islands consists of two small islands, each approximately
1/3 hectare (3/4 acre) in size. The islands have low, grassy vegetation
and therefore primarily provide habitat only for nesting terns. Each
year. since 1983, Ted D'eon of West Pubnico has been monitoring roseate
terns on the islands. This summer he found 418 tern nests of which 23
were roseate tern nests. All roseate tern nests were found on the more
northern of the two islands where most of the other terns also nested.
During a visit on July 2 1 s', Ted saw a number of young roseates flying
around and only found one dead chick. It appears that the roseate terns
have had a relatively good breeding season.
Awareness of the importance of the Brothers Islands to the roseate terns
has been through the Canadian Roseate Tern Recovery Plan and the Atlantic
Management Plan for Marine Terns. In response to this, the province,
through the Department of Natural Resources, recently acquired half
interest in one of the Brothers Islands. As soon as the Crown acquires
title to both islands it is proposed that the islands be declared a
Wildlife Management Area. This declaration will include regulations
for the protection and management of terns and their habitat but, on
a restricted basis, will also allow for human use.
The Brothers Islands will be managed according to the Canadian Roseate
Tern Recovery Plan. Interested individuals from the community, government,
and other groups, will assist the Department of Natural Resources with
management activities on the islands. These activities may include regular
surveys of roseate terns and other seabirds and estimates of their reproductive
success to act as indicators of the population's health.
The impact of gulls and other predators on terns will be assessed. Based
on this assessment it may be necessary to use barriers to keep predators
from tern nests or to implement a program of gull removal.
Small-scale habitat alterations may be carried out to improve nest habitat.
For example, more artificial nest structures, which have been shown
to increase reproductive success, may be placed on the island.
The Department of Natural Resources and the Canadian Wildlife Service
are interested in all species of terns. Roseate terns have threatened
status; however, common and Arctic terns have also both shown signs
of decline. We are keen to hear of any new tern colonies that you have
happened upon, or tern colonies that you have seen in the past, but
that have declined in numbers or have even disappeared. It is difficult
to identify all the tern breeding sites around the province, but with
your help we can track changes in the distribution and abundance of
these fascinating seabirds.