Thursday, April 18, 2013

The Blue-gray Gnatcatcher


Text and Photos by Laurie Sheppard

Spring is a special time for birders at Hagerman National Wildlife Refuge.  We expect many migrants to pass through on the Central Flyway, but spring is also a time when our summer birds return.  One of the first things these visitors, as well as many of our resident birds do is to search for a mate and begin to raise a family.  Nesting behavior is happening all over the refuge.  Sometimes it’s very obvious – a Great Blue Heron carrying a stick to the rookery beyond Harris Creek, a bluebird or martin sitting on a nest box near the Visitors Center, or a woodpecker hollowing out a nest in a dead tree at Dead Woman Pond.  Last weekend, I happened upon one of the less conspicuous nesters, but one of the more interesting.

Among the first summer visitors we hear, almost as soon as the leaves pop out, is the Blue-gray Gnatcatcher.  I say hear, because usually you will hear them before you see them. Everywhere you go, if there are trees, you will hear the buzzing Pzzzzz, Pzzzzz call of the busy little birds.  Smaller than a sparrow, the Blue-gray Gnatcatchers flit about looking for small bugs and spiders in the emerging leaves.  When you hear that distinctive sound, look high in the trees – often oak trees – and watch for movement.  Gnatcatchers constantly flick their tail when they are hunting.  They will continue to frequent the canopy throughout the summer and into the fall when they will head back south to avoid the cold weather. 

Male Blue-gray Gnatcatcher at HNWR
As their name implies, they are mostly steel gray with a conspicuous eye-ring.  There is often some black in their tail and they have white bellies and white outer tail feathers.  In breeding plumage, the male has a black line over each eye that meets in the middle just above his beak.  Because of their size, they are often hard to see, but if you’re patient and watch for movement, you will be rewarded.  That is how I found the nest-building pair.  I noticed that there were two birds in the tree and they repeatedly went back to the same branch.  I thought maybe it was a particularly good feeding spot but soon I realized they were carrying nesting material.  They were not terribly bothered by my presence so I took advantage and when both were off getting more supplies, I re-positioned myself to get a better look.

Female at the nest
I have since learned that the nest they built is typical of the species:  beautifully constructed of grass stems, bark strips, plant down, hair, feathers or other fine fibers held together with spider webs and caterpillar silk.  On the outside, it is camouflaged with tiny bits of bark and lichens.  Both parents participated in perfecting the nest, which is positioned on a level branch away from the trunk of their tree.  Soon there will be 3-6 pale blue eggs dappled with brown spots.

Male at the nest
To give you an idea of the size of a Blue-gray Gnatcatcher, an American Goldfinch is reported to be around 4.5 to 5 inches, and a Ruby-throated hummingbird 3 to 3.5 inches.  A Blue-gray Gnatcatcher is right in between at about 3.9 to 4.3 inches.  I have read that hummingbird eggs are the size of a Tic-Tac mint.  I imagine these will not be much bigger than that.

The Blue-gray Gnatcatcher is the only member of its species you will find this far north, and is the only truly migratory one. Predominantly, gnatcatchers are Neotropical residents but the Blue-gray Gnatcatcher can be found from the Pacific coast to the Atlantic.  In the west, the birds remain in the southern tier, but in the east you can find them all the way north into Maine.  Here in the central U.S., they are active all over Texas, Oklahoma, and throughout most of Kansas. 

Sources for technical material: Cornell Lab of Ornithology; Audubon Birds app for Android.

8 comments:

  1. Nice work Laurie.
    Phil McGuire

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  2. I really enjoyed this article and learned a lot! The amazing pictures were like the icing on the cake! Thanks so much for sharing!

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  3. What a great write-up! I want to find one now!! Thank you so much - and just amazing pics!

    Sally Bigley

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  4. Now that was a good read and excellent photos!

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  5. Now that was a great read and excellent photos!

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  6. Enjoyed the write up.

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  7. this article help me with my school science project so thanks for the article

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  8. Hmm, good job! This is really something!

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