Rare Bird Report 47-B-08

Idaho Bird Records Committee Seasonal Rarities Report

Species: Blue-winged Teal, female, winter report requested for species statewide

Reporter: Cliff Weisse, 4125 Beaver Springs Rd., Island Park, ID 83429, 208-558-7789, cliffandlisa@octobersetters.com

Other Observers: Darren Clark, clarkd@byui.edu    

Date of Observation: December 16, 2008

Date Report Prepared: December 17, 2008

Locality of Observation: In a warm water slough west of Rexburg.  

Habitat: Stream-not much open water around at the time so waterfowl was concentrated.

Conditions: Distance between 20 and 80 yards with Nikon 10 x 42 Premier binoculars and Swarovski 8omm Scope @ 20-60x.  Sun was behind observers and birds were seen in excellent light with excellent color discretion.  Total observation time about 15 minutes during two visits to the location on the same day.

Did you take notes… No

Did you consult a field guide or other reference work?
Yes, during the observation as well as later the same day

What guide or reference did you consult?

Sibley Field Guide to Birds of North America
National Geographic Field Guide to Birds of North America, 4th edition

Description(prepared from memory and photos): Overall brab gray brown dabbling duck.  Structure similar to Mallards but much smaller.  Feathers on flanks dark brown with buffy fringe.  Undertail coverts through vent dirty grayish white with darker brownish spotting throught.  There was no whiteish or buffy triangular patch along the sides of the tail on the undertail coverts/rear flank as shown by Green-winged Teal-undertail area was uniformly marked throughout.  Bill longer than expected for Green-winged Teal but not nearly as large as that shown by Northern Shoveler or Cinnamon Teal (neither of the last two species were present for comparison but GW Teal was present close by and observed shortly, perhaps two minutes, after our second observation of this individual).  Face pale brown with darker line through eye (dark lores and post ocular stripe), eye ring whitish and broken into crescents above and below eye (dark eye line continued through the eye ring).  There was an obvious, fairly wide whitish area adjacent to the base of the bill and extending through the throat.  Secondaries appeared dark in the field and I did not see green on them, although I saw the white line separating the secondaries from the coverts during a wings stretch.  At least some of the upperwing coverts were pale blue.

Behavior: This bird was on the water with Mallards and I don't recall seeing it forage.  It was not roosting at any time during observation.  When we got out of the car to take photographs it began swimming away from the bridge where we were parked.  I heard no vocalizations and saw no interactions with other birds.

How and when did you positively identify the bird, and what clinched the identification for you?  When I first noticed this individual I assumed it would be a Green-winged Teal as others were present in the immediate area and GWTE is the expected teal in winter.  When I observed the bird through binoculars I suspectedBlue-winged because of the face pattern and mostly because I could see there weren't pale triangular patches below the tail.  We left for a while to pursue other birds and returned before heading home to try to confirm the identification.  Close observation confirmed the field marks listed in the description.  To make sure we drove about .5 miles to where six Green-winged Teal, including one female, were on the water and the female shortly turned away immediately revealing obvious bright whitish triangles below the tail, even though it was about fifty yards away and viewed only through binoculars.  

How did you eliminate similar species, and what were they?  The fact that the white area at the base of the bill does not extend above the lores makes this a female.  Other female teals and perhaps Northern Shoveler and the unexpected Garganey could cause confusion.  
-Northern Shoveler has a much larger bill and females lack blue wing coverts.  
-Green-winged Teal is ruled out by the blue wing coverts and lack of the pale patches below the tail, which is shown by both sexes.  
-Garganey has atronger contrast in the face pattern and females lack the blue wing coverts

Experience with this species:  I am an avid birder and annually see hundreds of Blue-wingeed Teal, mostly in fall, dozens of Cinnamon Teal, and thousands of Green-winged Teal.

General experience birding:  14 years

Were photo(s), video, and/or audio obtained by you?  Photos-see below