Monday, September 10, 2012

Highlights of September 3-9th

Towards the end of this past week a strong cold front brought in an increased volume of fall migrants. More Swainson's Thrushes with the first Gray-cheeked thrush movement, the diversity of warblers increased, and the mosquitoes have lessened. Seventeen species of warblers were captured this week including Tennessee Warbler (TEWA), Nashville Warbler (NAWA), Northern Parula (NOPA), Yellow Warbler (YEWA), Chestnut-sided Warbler (CSWA), Magnolia Warbler (MAWA), Black-throated Blue Warbler (BTBW), Black-throated Green Warbler (BTNW), Blackpoll Warbler (BLPW), Black-and- white Warbler (BAWW), American Redstart (AMRE), Ovenbird (OVEN), Northern Waterthrush (NOWA), Mourning Warbler (MOWA), Common Yellowthroat (COYE), Wilson's Warbler (WIWA), and Canada Warbler (CAWA). Magnolia Warbler and American Redstart were the most abundant at Navarre. 
After-hatch year (AHY) male Wilson's Warbler (WIWA)
While the Magee Marsh Boardwalk is located on a smaller beach ridge making it possible to see most species there at any given time, the Navarre banding station is located on the largest remaining ridge. The station only occupies about 5% of the area. The Boardwalk this week reported many vireos, Cape May Warblers (CMWA), and Blackburnian Warbler (BLBW). None of these were identified at Navarre and only a few vireos. Micro-weather conditions play a role in where birds land to rest and feed for the day as well as the size of the habitat block.  Add the opportunity to be seen and migrating behavior and it is easy to highlight how such different impressions can be gotten by individuals.

A Quiz Bird for you to ponder while reading the rest of the post:

Many flocks of Red-winged Blackbirds (RWBL) have been flying over the study site during the first hour after sunrise. A small sample are caught in the nets. Here is a comparison of an adult (AHY) and hatching year (HY) male RWBL. HY male has body feathers similar to female this time of year with orange lesser coverts whereas the AHY male has black body feathers edged with brown which will wear off giving the solid black plumage. The HY male will molt his body feathers again before spring to a black body but still have its orange lesser coverts.
Back of AHY and HY RWBL

Front view of AHY and HY male RWBL
It is often difficult to identify Red-eyed Vireos because the HY birds have dark eyes; however, they still have the dark supercilium and eyeline stripe on their gray head, green back, wings (with no wing bars) and tail, a white belly, and blue-gray legs, like the adult.  They only lack the adult's red eye. By spring the eye has turned red like the adult birds.
AHY left and HY on right
Hint for Quiz Bird-Here is a second photo from the front:

A species that normally is gone by the first week of September is this one:
Yellow Warbler -note yellow tail spots-only found in YEWAs

YEWA adult (AHY) female with slate colored bill and tiny red streaks on breast

Some highlights for the week for you to enjoy:

HY Male Rose-breasted Grosbeak (RBGR).
You can see his rosy "wing pits" showing, identifying it as a male. 

HY male Ruby-throated Hummingbird (RTHU)
This coming week should see a good push of new birds. Get out and enjoy the season.  Quiz Bird Answer: HY male Mourning Warbler with its split eye-ring edged with white and the breast has the shadow of its spring black chevron.

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