Decoding the Traill's Flycatcher Complex

 CAPTAIN SAMS

We had a little more bird action today compared to the the last several days.  Despite the southerly winds migrants are still coming through. In fact, all of the new birds banded today were mostly likely migrants. 

We caught our third "Traill's" Flycatcher of the season. In years past, we used to take a series of intricate and "error-prone" measurements to try to separate "Traill's" into either Alder or Willow Flycatcher but starting last year we have been trying a new approach developed by Cin-Ty Lee and Andrew Birch. Here is a link to their paper if interested. This new approach is looking at the difference between the spacing between the tips of 5th and 6th primary feather, and the 6th and 7th primary feather on a folded wing. If the spacing between p6 and p7 is greater than the spacing between p5 and p6, then the bird is an Alder. If reversed, than the bird is a Willow. This method is reported to work on 95% of the birds. 

In the photo below, you can see that the distance between p6 and p7 is greater than the distance between p5 and p6, therefore this bird is likely an Alder Flycatcher. To get more even more precise, we can measure the distances between the two. I use a set of calipers to measure these distances from the photo on my phone. I then calculate the p6:7 ratio ([p6-p5] / [p7-p6]). If that ratio is greater than 1.05, the bird is a Willow Flycatcher. If the ratio is less than 1.02, the bird is an Alder Flycatcher. The ratio of the bird below is 0.91, therefore it should be an Alder. 

  

 -Aaron

    

LITTLE BEAR

Today at Little Bear only 15 birds found their way into our nets. Of the 8 species we captured, we had one first of season Yellow-breasted Chat! Chats are pretty neat birds. For a while scientists didn't know what family they belonged to. They were historically grouped with wood warblers until genetic analysis showed they weren't very closely related at all. These birds are also one of the few songbird species known to regularly sing in the middle of the night! Chats usually have a lot to say, and their song consists of a variety of noises including whistles, cackles, and even mimicry.

-Aiden

Yellow-breasted Chat (hatch year, female)

Species	Captain Sam's		Little Bear
	New	Recaps	New	Recaps
Downy Woodpecker	-	1	-	-
"Traill's" Flycatcher	1	-	1	-
Red-eyed Vireo	2	-	-	-
Carolina Chickadee	-	-	1	-
Blue-gray Gnatcatcher	2	-	-	-
Carolina Wren	-	-	-	2
Yellow-breasted Chat	-	-	1	-
Northern Waterthrush	6	1	-	1
Black-and-White Warbler	1	-	-	-
American Redstart	2	-	-	-
Prairie Warbler	7	-	-	-
Northern Cardinal	-	2	1	2
Painted Bunting	2	1	5	-

Today's Banding Stats	Captain Sams	Little Bear	TOTAL
# Birds Banded	23	10	33
# of Recaptures	8	5	13
# of Species	10	8	18
Effort (net-hours)	121.1	91	212.1
Capture Rate (birds/100 net-hours)	23.1	16.5	39.6
# of Nets	33	28	61

2026 Fall Cumulative Banding Stats	Captain Sams	Little Bear	TOTAL
# Birds Banded	202	54	256
# of Recaptures	88	19	107
# of Species	25	14	26
Effort (net-hours)	1333.3	367.9	1701.2
Capture Rate (birds/100 net-hours)	21.8	19.8	21.3
# of Days	11	4

Banding Staff

Aaron Given (CS)

Michael Gamble (CS)

Liz Held (LB)

Olivia DeMarchi (CS)

Jasmine Fu (LB)

Aiden Gifford (LB)

Note:  All banding, marking, and sampling is being conducted under a federally authorized Bird Banding Permit issued by the U.S. Geological Survey’s Bird Banding Lab.