Wednesday, June 11, 2014

Prairie Warbler, Bobolink and Woodthrush

[Port Huron SGA, MI. June 2014]

If you look at the range map for Prairie Warbler in Michigan, it will be clear that this attractive species may be found patchily in Summer along the Lake Michigan shoreline in Western Michigan.

Thanks to a tip from Joanna, a Detroit Audubon Society birding leader, a spectacular male was found in Southeast Michigan in Port Huron SGA. The complete list of species observed on this excursion was:
  • Prairie Warbler
  • Wood Thrush
  • Bobolink
  • Rose-breasted Grosbeak
  • Blue-winged Warbler
  • Common Yellowthroat
We lead with the Prairie Warbler:


Prairie Warbler seen at Hewitt Rd trail, Port Huron SGA

There are two subspecies of the Prairie Warbler found in the US -- a Northern race which is entirely migratory and a Southern (or Florida) race which is a permanent resident in the mangroves of South Florida.


Northern Prairie Warbler (note chestnut patch on back; top image)

While both are largely similar, there are some subtle differences (see a Florida Prairie Warbler here):
  • The Florida subspecies is larger (5" vs. 4.5")
  • The Northern race has bolder facial markings
  • The Florida subspecies lacks the chestnut patch on the back
  • The Florida subspecies shows more white on the breast
The population of the Prairie Warbler has contracted dramatically -- they are listed as a state endangered species in Michigan. Loss of habitat and brood parasitism by the Brown-headed Cowbird are the leading causes.

In most of the entire Eastern US, the haunting song of Wood Thrush resonates in the woods:


The Wood Thrush's song is made possible by a "Y" shaped voicebox that can generate two different notes simultaneously creating a mellifluous and unforgettable harmony. The species population has declined by over 50% since the 1960's.

While the Red-winged Blackbird is the first Icterid to arrive in Michigan, the Bobolink is the last:


Wintering in Argentina, it is small wonder that covering all that distance to North America (breeding as far North as Canada), takes till early Summer. This iconic blackbird is a rapidly declining species of grasslands even though its global population is 8 million.

Other species observed included Rose-breasted Grosbeak:


Blue-winged Warbler:



And, Common Yellowthroat:



Common Yellowthroat

Breeding ranges are dynamic -- for example, just a few years ago, Golden-winged Warbler was a regular breeder at Port Huron SGA. Sadly, they are no longer found in SE Michigan. Thus, it is a tremendous opportunity when an irregular breeder in these parts, such as the handsome Prairie Warbler, graces the forest with its unmistakable song and bright charisma.

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