Thursday, November 9, 2017

Migration Fallout Drops Vireos

Rare Vireos 'Everywhere'


Adult White-eyed Vireo
The recent migration fallout brought reports of White-eyed and Yellow-throated Vireos from all areas of the fallout zone, Grand Manan, Campobello and southwestern Nova Scotia.  Flocks of these migrating vireos were put down by the storm and strong winds.

Vireos are about the size of warblers (13 cm/5 in) and look much like them but appear chunkier.  They live in trees and bushes and feed on insects, spiders, seeds and berries.  In New Brunswick we normally have 4 species; Red-eyed, Blue-headed, Warbling and Philadelphia Vireos.  White-eyed and Yellow-throated Vireos are rare here.

Shown above is the White-eyed Vireo. This species loves thick low bushes and is usually discovered by its bursts of raspy song.  It is a good mimic and usually sings loudly mimicing several different bird songs.  

Juvenile White-eyed Vireo [Jennifer Pierce Photo]

There are only two bird species in North America with white eyes, the White-eyed Vireo and the Wrentit (from the west coast).  The young White-eyed Vireo (shown above) has a dark eye until the next spring when it turns white.  

The Yellow-throated Vireo is slightly bigger than the White-eyed but is shaped much the same.  It normally lives high in the canopy of deciduous trees.  It feeds on insects and small fruits.  Its song is not as loud or abrupt as the White-eyed.  It is a slow 2 or 3-syllable phrase with long pauses between sometimes depicted as 'three-eight three-eight three-eight'.  

Yellow-throated Vireo [Jennifer Pierce Photo]
The brilliant yellow of the Yellow-throated Vireo is distinctive.  Note, in the photo above, the brilliant yellow on the throat, spectacles and breast.  That bird is hard to miss!  The eye is always dark and the bill is thick like all vireos.  Yellow-throated Vireos need large tracts of land to breed successfully (at least 250 acres).  As a result of landscape fragmentation, their breeding success has become threatened in recent years.  

Yellow-throated Vireo [Internet Photo]
White-eyed and Yellow-throated Vireos breed in summer in the eastern US and winter in the very southern part of the eastern US, Mexico and the Caribbean Islands.  The flocks that landed here during the recent severe storm obviously got blown off course in their southward journey.  Fortunately they found good weather here which would have provided sufficient insects, spiders and small fruits to allow them to renew their entry stores so they could return to the south.  Come again beautiful vireos!

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