Monday, August 30, 2010

More Fall Migrants and An Interesting Goldfinch

21-28 August

I banded five days this past week. Migrants have increased a bit from the previous week and I'm hoping the following week will be even better. On Saturday the 21st we captured two more American Redstarts, this time both hatch year males.

At this time of year, hatch year male restarts can look very much like adult females. We sex them by the contrast of darker breast coloration compared to a more lemon yellow color under their wings and by the dark gray rump feathers contrasting with paler gray back.

A very exciting capture for us was a Least Flycatcher, a first for the station!

The plumage is grayer than in the other flycatchers I tend to capture. They may also have a slightly paler edge to the outer webbing of the outer tail feather as shown below:
All the measurements fit the bill for Least Flycatcher too.

We captured a young molting Northern Cardinal who displayed a varied color scheme to his feathers.

The very brown feathers are retained juvenal feathers that he will probably molt this year, as he was in the middle of his first prebasic molt, although sometimes they will retain some juvenal seconday feathers, the longer feathers closer to the body.
We were happy to have more Northern Mockingbirds this week. This one still had some retained spotted juvenal feathers on the breast.

For some reason this bird also retained it's median coverts (the more worn and brown small feathers near the top of the wing) and replaced it's greater coverts (those fresher, blacker feathers directly below the med covs) but may finish molting on the wintering grounds.
The underparts of hatch year Great Crested Flycatchers are developing more yellow as they molt. Some were just starting to in my last post.

As hatch year birds molt into their adult plumage, banders have to find other ways to age birds. One way is to check for a molt limit in their wing. Adult birds will go through a complete molt, but the young of many species molt only some of their feathers. This Great Crested has a molt limit in the greater coverts. You can see the replaced inner six blackish coverts with light edging compared to the retained four juvenal browner and buff edging of the remaining outer coverts.

Below a young female towhee is developing her adult body plumage,

and here is her hatch year male counterpart.

 Although not a migrant, I had an interesting recapture of a male American Goldfinch on Saturday the 21st. This bird was first banded as a second year male (born in 2005) in April, 2006. Three years later I recaptured him on August 25, 2009. Goldfinches are one of our latest breeders and I expected to find him in breeding condition with an enlarged cloacal protuberance. But I was extremely surprised to find he had a full brood patch too! As I explained in a previous post, females develop vascularized bare bellies with fluid to incubate eggs. In some species males will develop partial brood patches if they help incubate eggs, but male goldfinches don't take part in this behavior. Below is a picture from 2009. It is not just the case of a female that has male-like plumage as an enlarged cloacal protuberance is visible below the belly.
Also the plumage was clearly an older adult male.

I captured this same bird  last weekend on the 22nd. He displayed the same phenomenon.

On the side view you can see the enlarged cloacal protuberance (we call it a CP).

This is probably the case of some kind of hormonal imbalance specific to this bird and not an endocrine disrupting environmental toxin or we would probably find it in other male goldfinches in the area, which I haven't .

Rainy days prevailed Monday - Wednesday so didn't get out to the nets again until Thursday the 26th. It was nice to pick up another Blue-winged Warbler, this time a hatch year male.

Hatch year Prairie Warblers were captured most days including this female Prairie. She had no chestnut feathers on her back and had less distinctive black streaking to her sides.

This poor adult Song Sparrow of unknown sex really needed to get going on replacing it's feathers! The feathers were in such poor condition all that was left of the middle tail feathers were the shafts.

The wing feathers were poor too.

Our first Yellow-bellied Flycatcher showed up on Thursday,
and we banded three Traill's Flycatchers this week.

On Friday I captured our first hatch year goldfinches.
Gretchen and I had 19 species of birds banded on Saturday including this gorgeous hatch year male Yellow-breasted Chat.

First year chats go through an incomplete molt which banders refer to as an eccentric sequence, meaning they start their flight feather molt in an atypical pattern molting outer primaries and inner secondaries. This bird however molted its outer 6 primaries (p4-p9), primaries 1-3 are retained, molted his first secondary feather and secondaries 2-6 are retained. The molted feathers are darker in color with dark brown shafts as opposed to the lighter brown juvenal feathers and chocolate colored shafts.  
It's not often we capture Scarlet Tanagers, so we were happy to capture this first year male. Young males look similar to adult females with their lime green body plumage, except that as they molt their wing coverts come in black and contrast dramatically with the retained juvenal feathers. You can see this bird has started
molting his lesser coverts, those black feathers at the top of his wing.
Scarlet Tanagers have a "tooth" visible on the edge of the upper mandible (bill).

Thanks to those who helped this week- Gretchen Putonen, Carolyn Kenndy, and Judy Keller.The following birds were seen, heard, or captured during 21 – 28 August. Numbers reflect captured birds only.
Total Birds: 322                                       Total Species: 53
Total Banded Species: 26                         Birds/100 net-hours: 60

Great Blue Heron
Mute Swan
Black-bellied Plover
Greater Yellowlegs
Least Sandpiper

Laughing Gull
Ring-billed Gull

Herring Gull
Great Black-backed Gull
Common Tern
Mourning Dove
Ruby-throated Hummingbird- 11
Belted Kingfisher
Red-bellied Woodpecker
Downy Woodpecker- 4
Hairy Woodpecker
Yellow-shafted Flicker
Yellow-bellied Flycatcher- 1
Least Flycatcher- 3 (same bird captured 3 of the days)
Traill's Flycatcher- 3
Eastern Phoebe- 7
Great Crested Flycatcher- 4
Eastern Kingbird
Tree Swallow
Barn Swallow
Blue Jay- 1
American Crow
Fish Crow
Black-capped Chickadee- 39
Tufted Titmouse- 6
Red-breasted Nuthatch
White-breasted Nuthatch
Carolina Wren- 3
House Wren- 3
American Robin
Gray Catbird- 162
Northern Mockingbird- 3
Cedar Waxwing
European Starling
Red-eyed Vireo- 3
Blue-winged Warbler- 1
Prairie Warbler- 4
American Redstart- 3
Common Yellowthroat- 19
Yellow-breasted Chat- 1

Scarlet Tanager- 1
Northern Cardinal- 2
Eastern Towhee- 3
Song Sparrow-16
Baltimore Oriole- 4
American Goldfinch- 5

House Sparrow


Wednesday, August 18, 2010

Midsummer Birds

1-16 August
I started the month doing some hummingbird banding in my backyard capturing a few hummers. One was a young male who hadn’t started his molt yet. Young males have streaked throats before filling in with red gorget feathers. Notice the buff edged body feathers, a good indicator of age. In the hand you can see grooves on the side of the bill that will gradually wear off with age, but you need a good set of magnifiers to see them!
Another hatch year male captured ten days later was further along in its molt.

The nets during the first two weeks of August have been full of birds. Surprisingly we captured no American Goldfinches, one of the more common birds in our mist nets. They are one of our latest nesters and I assume they are busy sitting on eggs.

On August 2nd we captured 90 birds of 18 species, two of those being our first Great Crested Flycatchers for the year. Both were hatch year birds. They constantly clap their bills together to produce a SNAP type noise and are the largest flycatcher that we handle.

They were beginning to molt in yellow feathers on their undersides.

Cinnamon-edged coloring is present on their rump, wing and tail feathers.

Occasionally during the course of net checking we’ll notice a huge flock of starlings headed for one of our nets. “NO!” we silently pray, hoping they will elude getting caught. Luckily we only caught four hatch years today from a large flock that was visible flying around our meadow nets. It isn’t very often that I capture a picture of a starling NOT in this pose as you’ve seen in previous pictures:

They were in various stages of their first prebasic molt. Their feathers are stunning even if some consider them trash birds due to their non-native status.

Eye color can be a key to sex, with the male being dark brown and a yellow ring surrounds the iris in the female.


Flickers rarely get caught because they are so large and tend to bounce out of a mist net. They are extremely vocal in the hand screeching so loudly they actually hurt our ears! We captured a hatch year male today.

These are hefty birds and weigh at least 10x what a chickadee weighs, barely fitting on our scale. Notice the beautiful yellow coloring to the shafts of their wings and tails. Their western counterparts have red coloration in place of the yellow. Here is the flicker getting weighed which takes only a few seconds.

We’ve had plenty of Baltimore Orioles these past two weeks both in our nets and in my hummingbird trap at my home. Below is an adult male looking quite fresh as he finishes up his annual molt.

They scoff down hummingbird nectar so fast I’m constantly filling the feeders. Orioles flock together in large groups this time of year. This adult female has black spots on her back and head.

This young male oriole was especially bright from munching on Tartarian honeysuckle berries.

The best bird of the day from Thursday August 5th was a beautifully plumaged adult male Blue-winged Warbler just finishing up his molt. Besides insects, he may have been munching on the same berries as the oriole above with his orange tinged feathers.

We had a good variety of birds on Saturday, Aug 7th with 20 species banded and we handled a whopping 53 catbirds. Our first hatch year kingbirds appeared

and numerous young towhees.

Before their first pre-basic molt we can sex hatch year towhees by their tail color, black in males

and brown in females.

We also captured another adult Ovenbird looking a bit ratty going through its annual molt

and our first White-breasted Nuthatch for the year, a hatch year male.

The combination of black, white, and bluish-gray feathers is so pretty isn’t it? While there is no shortage of these nuthatches, we don’t capture them very often.

Also making an appearance on Saturday was a young House Wren

and a first year female Hairy Woodpecker who was extremely uncooperative getting her picture taken. The best I could do was a bit blurry photo

and my fingers paid dearly for the effort! OUCH!

On Wednesday, August 11th, I banded in North Eastham in the National Seashore. I had a contract job with a group of researchers studying the reasons behind the lower incidence of Lyme disease in the south compared with other parts of the country. They needed a bander who could mist net birds and remove ticks. Five nets were set up in one of their plots where they are also sampling mammals, rodents, and reptiles (reptiles mainly in other parts of the country). We met before dawn and opened nets as the sun rose. They had set up nets the night before in the woods and we caught nothing for the first two hours. After scouting out the area I suggested we move a couple of nets to a more appropriate area, more shrubby than woodsy, and from then on we had birds every net round. We did resort to a bit of clowning around we were so happy to finally get some birds.
Eric releasing a Hermit Thrush

Eric is a wildlife biologist contracted to help them with the other wildlife they are sampling. Two students from the University of Rhode Island learned about bird banding and helped to band birds and remove ticks. Here is Justin releasing a Blue Jay.

Both Justin and Amanda took turns looking for ticks on the birds:

We handled fourteen birds for the morning with half of those being hatch year Hermit Thrushes.

Most of them were molting body feathers. Notice the hole under the bird’s eye- that is actually the ear!

The reddish tail is characteristic of Hermit Thrushes, who breed on Cape Cod. They have one of the most beautiful songs of all our songbirds.

Amanda found an interesting, brilliantly colored spider she shared with us found in the leaf litter. Apparently it is called an Arrow-shaped Micrathena (female).

I had an enjoyable morning with a fun group of people. Seated is Jean Tsao, the lead investigator from the University of Michigan and Howard Ginsberg, another researcher and professor at URI is standing next to her.

The following day I banded another hatch year Red-eyed Vireo back in Brewster at the banding station.

I also captured the Gray Catbird with the grossly deformed bill I spoke about in my last post. It weighed only a gram less than last time, but felt emaciated in my hand.

We netted more Northern Waterthrushes on Saturday, Aug 14th.

Our first American Redstart for the year showed up today too, a hatch year female.

Below is a comparison of eye color in an adult Northern Mockingbird that we caught today. Adults have a yellowish tinge to the iris. She also had a slightly deformed bill.

The young mockingbirds have a grayish coloration to their iris which will gradually turn yellow as they age.

The best bird on Saturday was a hatch year Mourning Warbler of unknown sex, but probably female. She was just passing through on her southerly migration journey to build up some fat reserves. She had some fat on her, but will probably stick around for a few days before moving on.

Monday, August 16th proved questionable weather-wise, but Judith and I gave it a try only opening enough nets that we could handle in case the rain come in faster than expected. Luckily with technology today I’m able to keep an eye on the radar on my phone and we had a successful morning with just a wee bit of rain that didn’t amount to anything and had a good number of birds for our effort- 63. We had nothing new in the way of birds but Judith did catch something other than a bird. She quickly called me on the two-way radio so I could run down and take a picture. It was a Long-tailed Weasel! Judith remembers a buffy coloring to the undersides, which would indicate weasel rather than mink. All I can say is good thing Gretchen wasn't there!

As usual I’m grateful to the volunteers who helped out at different times throughout the last two weeks- Gretchen Putonen, Judith Bruce, Carolyn Kennedy, Roger Mongold, and the Johnson family- Sheryl and her daughters, Lauren and Kristen. The following birds were seen, heard, or captured during 1 – 16 August. Numbers reflect captured birds only.

Total birds: 466 (+ 14 Eastham birds)          Total species: 57

Total banded species: 31                             Birds/100 net-hours: 96

Double-crested Cormorant
Great Blue Heron
Green Heron
Black-bellied Plover
Least Sandpiper
Laughing Gull
Ring-billed Gull
Herring Gull
Great Black-backed Gull
Mourning Dove
Black-billed Cuckoo
Great Horned Owl
Ruby-throated Hummingbird -20
Belted Kingfisher
Downy Woodpecker -5
Hairy Woodpecker -2
Yellow-shafted Flicker -2
Traill's Flycatcher -1
Eastern Phoebe -12
Great Crested Flycatcher -4
Eastern Kingbird -9
Tree Swallow
Barn Swallow
Blue Jay -1  (in Eastham)
American Crow
Fish Crow
Black-capped Chickadee -46
Tufted Titmouse- 3
Red-breasted Nuthatch
White-breasted Nuthatch -1
Carolina Wren -4
House Wren -3
Hermit Thrush -7 (in Eastham)
American Robin -6
Gray Catbird -200
Northern Mockingbird -4
Cedar Waxwing
European Starling -5
Red-eyed Vireo -1
Blue-winged Warbler -1
Yellow Warbler -7
Prairie Warbler -1
American Redstart -1
Ovenbird -1
Northern Waterthrush -2
Mourning Warbler -1
Common Yellowthroat -36
Northern Cardinal -5
Eastern Towhee -9
Saltmarsh  Sparrow
Song Sparrow -52
Baltimore Oriole -20
Purple Finch
House Finch -1
American Goldfinch
House Sparrow