Bermuda’s Eastern Bluebird is featured in the latest series of four stamps, released today by the Philatelic Bureau of the Bermuda Post Office.

The stamps are available in values of 35 cents, 85cents, $1.10 and $1.25.

The 35 cent stamp shows a male bluebird — identified by its bright blue upper parts and rusty red breast — perching on a Bermuda cedar (Juniperus bermudiana) branch.

The 85 cent stamp is represented by a female bluebird lying in its nest of dried grasses inside a nesting box and the $1.10 stamp shows a male, probably encouraging a female to build a nest in the box.

The $1.25 stamp displays the differences between the male and female bluebird. The female on top of the box is much duller in colour. In contrast, the male is more vibrantly blue. The stamp shows the male indulging in display behaviour to entice the female into using the box.

This year marks the 60th anniversary of the Bermuda Audubon Society, which was founded in part to save Bermuda’s population of bluebirds.

The Eastern Bluebird (Sialia sialis) is called “Eastern” because its habitat in North America is east of the Rockies. Bermuda has the distinction of being its only breeding location outside North America.

The bluebird is seven inches long. It feeds on earthworms, cut worms and caterpillars and also berries. Once it nested in cedar trees but now it almost always relies on nesting boxes for breeding.

The female is solely responsible for building the nest and for incubating the eggs. It lays four or five pale blue eggs between March and August. They take 13 to 15 days to hatch.

Every year the Audubon Society holds a workshop on building bluebird boxes to the correct specifications. The boxes are usually made with spruce or pine shelving. The entrance hole is one and a half inches wide, effectively keeping out starlings.

It’s unclear when the species first arrived but it had definitely settled on the Island by 1829 and is now one of Bermuda’s best loved native breeding birds. Seventy years ago bluebirds mostly nested in cedar tree cavities. The house sparrow (passer domesticus), introduced in the early 1870s, and the European starling (Sturnus vulgaris), colonising in the 1950s, gave the bluebirds heavy competition for nesting sites while the great kiskadee (Pitangus sulphuratus), was deliberately introduced in 1957 to control the lizards, included baby bluebirds in its diet.

The bluebirds’ plight was made particularly bleak when during the 1940s and 1950s a scale insect decimated the majority of Bermuda cedars.

In 1954 the Audubon Society came to the rescue by introducing a nesting box scheme. Since then hundreds of nest boxes have been erected on Bermuda’s golf courses and in parks and gardens, thus halting the Eastern Bluebirds’ decline in population.

The next stamp issue scheduled for release will be Bermuda in Bloom Part One — a new definitive series and the proposed release date is July 17, 2014.