Monday, 21 April 2014

Bobolink - An Amazing Journey of a Song Bird


An Amazing Journey of a Tiny Song Bird

When a diminutive sized song bird after nesting in the Prairies and cultivated lands of Canada and Northern parts of united states begins its journey to migrate to the grasslands and marshes in Argentina before the onset of winter every year it has to travel an extraordinary distance of 5000 miles and return to the Northern America again in spring and summer covering a total of awe-inspiring distance of 10000 miles ie (16000 kms) every year after year till its survival. The vast journey for survival is more remarkable in relation to the bobolink’s miniature size, averaging 7 inches in length, 11.5 inches in wingspan, and 1.5 ounces in weight. It is easily one of the world’s most inspiring migrant song bird.

A migrating Bobolink can orient itself with the earth’s magnetic field, thanks to iron oxide in bristles of its nasal cavity and in tissues around the olfactory bulb and nerve. They also use the starry night sky to guide their travels.

Normally a daylight forager, the Bobolink sometimes feeds after dark on bright nights during migration, to build fat reserves for its long flight over the Gulf of Mexico.

 
Bobolink (male) seen in its natural grass land habitat in Madison county 

Bobolink (female) seen in its natural grass land habitat in Massachusetts county


Bobolink moults twice a year, completely changing all their feathers on both the breeding and wintering grounds. When the male grows new feathers on the wintering grounds they all have yellowish tips, so he still looks like a non breeding bird. Eventually the pale tips wear off to reveal his striking black-and-white breeding colors.


Males are distinctive in their breeding plumage with a black and white rump and black and yellow nape, though their yellowish brown winter plumage is similar to the females'. In summer, bobolinks feed primarily on insects, switching to grain crops as they migrate south. The female builds the nest on the ground, in which she lays 5 to 6 eggs that incubate for about 13 days.


When you hear the fields singing, the pastures and prairie remnants of the Midwest. One can easily see the Bobolinks have returned from their long migration and are populating the grasslands again.
 



Bobolinks are related to blackbirds, which are often polygamous, meaning that males may have several mates per breeding season. Bobolinks are polygamous, too—but they’re also often polyandrous: each clutch of eggs laid by a single female may have multiple fathers.


 Male and Female Bobolink during their spring / summer breeding in Massachusetts


Bobolink numbers have been in decline since the middle of the 20th century, averaging a 3.8 percent decrease from 1980-1996. In North America, the loss of birds is mainly attributed to changes in land use, but it is suspected that winter survival is the main source of decline.
 
The bird is protected by the Migratory Bird Treaty Act in the US and Canada and is listed as a Species of Several Concern in several states. The Conservancy protects breeding areas and migration paths for the species.

Throughout its life span, it may have traveled the equivalent of 3 or 4 times around the circumference of the earth. 

The oldest Bobolink on record was a female known to be at least 9 years old.

  Post and Images by 



ThirdEye Reflections
Nature and WildLife Photography
By
Shekhar Bopardikar