Bird Banding Procedure (Click on any photo to enlarge)

The migration seems to be picking up a little at Connecticut Audubon Birdcraft Museum in Fairfield, Connecticut.  Today we banded 9 birds and recaptured two birds we had previously banded, 1 Ruby-crowned Kinglet, 2 Brown Creepers, 1 Golden-crowned Kinglet, 1 Eastern Phoebe, 1 Swamp Sparrow, 2 Hermit Thrushes and 1 White-Throated Sparrow.  The recaptures were a Hermit Thrush banded on 11/9/11 and a White-throated Sparrow banded on 11/8/11.  Both had been juveniles when we banded them last fall, so they had a good winter and are ready for migration back north as one year old birds.  I thought it might interest those who have never watched banding to see some of the steps so I had a fellow bander take pictures as I banded a Hermit Thrush.  We capture them in mist nets, nets so fine the birds don’t see them. When we take the birds out of the nets, we put them in cloth bags which calms them down.  After removing the bird from the cloth bag, the first step is to identify the species.  When I held him under the light, the rufous tail feathers positively identified this bird as a Hermit Thrush.

The bird is carefully removed from the bag

The bird is carefully removed from the bag

His reddish tail identifies him as a Hermit Thrush


His reddish tail identifies him as a Hermit Thrush

Now that we know what species the bird is, we are able to band it.  The band is an aluminum strip, closed into a ring, each with a unique number.  I pick the size band recommended by the US Fish & Wildlife Bird Banding Lab to fit a Hermit Thrush (1B), open up the ring, fit it around the bird’s leg and close it securely, using special pliers.

We check for fat by blowing on the "wishbone" area, where the fat is visible.

We check for fat by blowing on the “wishbone” area, where the fat is visible.

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Then the bird must be checked for age.  There are several ways to tell a bird’s age; skull ossification, molt patterns, retained juvenile plumage, and eye color being just a few.   In this case I can tell by looking at the feather pattern on the wing.  This bird has what are called shaft streaks, pale coloring on some of the feather shafts in the feathers over the inner part of the wing above the longer feathers (secondary wing coverts) which marks him as a bird that was born last summer.

These pale streaks on the feather shafts indicate he was born last year.

These pale streaks on the feather shafts indicate he was born last year. 

He weighs 30 grams

He weighs 30 grams

I then check the length of his wing (wing chord) and look to see how much he has been eating by checking his fat level.  This is done by blowing apart the feathers in the “wishbone” area where the fat deposits show up yellow against the red muscle, easily seen through the skin.  I need to see if I can tell which sex it is.  Some birds have different plumages in males and females but Hermit Thrushes can only be sexed while breeding, during which time they develop sexual characteristics around the cloaca.  The males have a protuberance so they can transfer their sperm to the females.  The females develop a brood patch where the feathers on their bellies disappear and the exposed skin becomes engorged with blood, making a nice warm area to put next to her eggs, but it is too early in the season to tell on this bird.  The bird is then placed in a net bag and weighed then finally, released back into the wild, unharmed.  All that remains to be done is to submit the data to the Bird Banding Lab where all records are kept.  These studies are vital for studies of population trends, migration information and many other scientific projects.

He's back on his way north sporting a shiny new bracelet.

He’s back on his way north, sporting a shiny new bracelet.

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