Today was an extremely slow day out at Captain Sam's! We had a total captures of 28 birds in the 6 hours we were out banding. The majority of our captures during this time of year are always Yellow-rumped Warblers. So, I decided to do a featured post about aging and sexing the confusing plumage of fall Yellow-rumped Warblers! Sorry in advance, this might get a little technical and boring!
The first thing you should always remember about aging and sexing any species is that no one characteristic is going to give you all the answers every time! When we look at aging and sexing yellow-rumps we typically look at many characteristics before we come to a conclusion. These characteristics could be things like:
-Molt limit!!!
-Wing Chord
-Skull
-Shape of primary feathers
-Tail shape
-Upper tail coverts
-Lesser and median coverts (Shoulder)
-Back feathers
-Face
Some plumage characteristics typically vary by sex and make it possible for us to accurately age and sex 95% of these warblers in their, seemingly, drab fall plumage. Upper tail coverts (coverts laying dorsally on the tail and posterior to the rump) are one example of these characteristics that give us an idea of what sex the individual could be. However these characteristics are highly variable and overlap in many cases as demonstrated in the diagram I created below.
Other characteristics that can vary by sex are the lesser and median coverts (shoulder feathers) and the back feathers. The amount of blue in the shoulder and the amount of black in the centers of the back feathers are also useful for determining sex. Again these characteristic are highly variable and sometimes hard to distinguish but can be used in conjunction with other criteria to age and sex individuals. I compiled another diagram to show this variation. (to view larger please click on the image)
Aging and sexing birds can be extremely valuable data to have. We can potentially utilize this information during migration studies to understand movement patterns, populations size, flocking behavior, and so much more!
Thanks for reading along! I hope you learned a little and enjoyed this post!
-Kristen
Little Bear
Today marked the end of the banding
season for Little Bear. Sadly the wind
limited our efforts and in the short time we were opened, we caught 5 new birds
and recaptured 3, representing 3 species.
Today also marks my last day of the season. This was the first season I worked at Little
Bear full time and it was quite the experience.
We started the season off with an
alligator hanging out in the net lanes and hurricane Irma threated to put an
end to the season early. The end of September
was by far on of the busiest stretches we have ever experienced at Little
Bear. Thanks to that stretch, we had our
best season yet for new birds with over 3,500 birds banded. October and November seemed to be a bit slower
than previous season and have been due to a change in habitat structure and
Little Bears inability to handle strong wind.
Aaron still has the rest of the month to go for Captain Sam’s and I want
to wish him best of luck and let the Yellow-rumped Warblers be ever in his
favor. Be sure to check back in during
the first week of December for a full season wrap up.
-Mattie
| Species | Captain Sam's | Little Bear | ||
|---|---|---|---|---|
| New | Recaps | New | Recaps | |
| Common Ground-Dove |
1
|
1
|
-
|
1
|
Yellow-bellied Sapsucker
|
1
|
-
|
-
|
-
|
Eastern Phoebe
|
1
|
-
|
-
|
-
|
Ruby-crowned Kinglet
|
4
|
-
|
1
|
-
|
Hermit Thrush
|
-
|
1
|
-
|
-
|
Gray Catbird
|
-
|
4
|
-
|
2
|
Chipping Sparrow
|
1
|
-
|
-
|
-
|
Swamp Sparrow
|
-
|
1
|
-
|
-
|
Yellow-rumped Warbler (Myrtle)
|
11
|
2
|
4
|
-
|
| Banding Stats | Captain Sam's | Little Bear | TOTAL |
|---|---|---|---|
| # Birds Banded |
19
|
5
|
24
|
| # of Recaptures |
9
|
3
|
12
|
| # of Species |
8
|
3
|
8
|
| Effort (net-hours) |
158.9
|
39.2
|
198.1
|
| Capture Rate (birds/100 net-hours) |
17.6
|
20.4
|
18.2
|
| # of Nets |
28
|
18
|
46
|
Banding Staff
Aaron Given (LB/CS)
Mattie VandenBoom (LB/CS)
Michael Gamble (CS)
Kristen Oliver (CS)
