More than with most species of small birds, the attention and interest of the observer center about the nesting habits of the blue-gray gnatcatcher because of the great beauty of its nest.
~Francis Marion Weston, 1949
One of my favorite spring arrivals is the plucky little blue-gray gnatcatcher. It is tiny, but bold. It looks a bit like a tiny mockingbird, but builds a nest like a large hummingbird. My friend, Mary, found a nest at the Garden recently and emailed me where to look as I prepared for a program. I never did find that one (they are often very well camouflaged on a branch). But, a week later, as I was leaving work, I heard the familiar “Steeve” call, looked up, and saw one fly into a small tree. I got out my binoculars, and was pleased to see a nest in progress.
A few evenings later, I brought my camera and spent some time watching this industrious duo go about the business of finishing what is certainly one of nature’s most beautiful nests. By this time, it looked like the nest was nearing completion, but the gathering of materials, and fine-tune adjustments, continued for over an hour as I watched.
The nest is a deep (about 3 inches) cup about 1.5-2 times the size of a ruby-throated hummingbird nest. Otherwise, they look almost identical – a somewhat high-walled, elastic nest covered on the outside with lichens and held together with spider silk. The inside is lined with soft materials like plant down, hair, and fine feathers.
As I watched, both adults were busy contributing to the efforts. During the breeding season, the male blue-gray gnatcatcher (photo above) can be distinguished from the female (photo below) by the presence of their black forehead and supercilium (a stripe that runs from the base of the birds beak and above its eye). The female’s head is plain gray.
I had my big telephoto plus a teleconverter, so I was well away from the nest. The birds chose a very busy location for their activity, right next to a road and walkway that is popular with Garden visitors, so I don’t think they minded me watching them.
There were times when nothing happened at the nest for 10 minutes or so, then there were bursts of activity with a bird bringing in materials (especially crustose lichens – they look like lichen cornflakes) every minute or so. The usual routine was to fly into a branch next to the nest, pause, then hop into the nest and place whatever material was brought in. Then there was often some fine-tuning, placing the lichen just so, inspecting it for a second, and then off again. Time spent in the nest on any one visit was usually less than 20 seconds. References say it takes about a week to complete a nest, but I think this pair could do it much faster based on what I saw.
In between nest-building activities, the pair would pause for some singing, preening, or the important duty of nest protection. I am a bit worried about this particular nest, since it seems in a more open location than many I have seen. There are a lot of hazards to any nesting bird, especially one so tiny. I witnessed a few bouts of territorial defense as this pair chased after a crow and a pair of blue jays that flew through their air space. And a pair of brown-headed cowbirds received a lot of attention when they perched within 50 feet of the nest. Both adults repeatedly dive-bombed the cowbirds, who seemed uninterested. They eventually flew off, and nest building resumed about 5 minutes later.
The final stage of nest building is refining the shape of the cup. This is something they put their whole body into…the adult plops down into the nest with just their head and long tail (the tail accounts for about 45% of the total body length) visible and pushes against the sides of the nest, shaping it as they rotate their body around, flexing the sides until it is just right.
At times, I could barely see their head at all, with just the slender bill projecting above the lichen wall. I checked on the nest the next few days and saw no activity, so I figured they had completed construction. And now, I see the female sitting in the nest for long periods of time, so I assume she is incubating her eggs. I will keep you posted on their progress.