Bluebirds feed spiders to their chicks because spiders can be a valuable food source during nesting season. I photographed this female Eastern Bluebird in my Arkansas yard as she carried a large spider for her young.
It was a small moment, but it showed an important part of raising young bluebirds.
Bluebirds Feed Spiders for Growing Chicks
Eastern Bluebirds feed their chicks many kinds of small prey. Insects make up much of their food during the warmer months, and spiders are part of that diet.
This female bluebird had picked a large spider, which made a good meal for hungry nestlings. Chicks grow fast, so the adults need food that is easy to carry, easy to swallow, and rich enough to help fuel that growth.
Spiders fit that need well. They are soft-bodied compared with many hard-shelled insects. That can make them easier for young birds to handle.
They also offer more than simple protein. Research on other insect-eating birds has shown that spiders can contain taurine, an amino acid tied to development in young birds. That does not mean this bluebird was making a scientific choice. It means her feeding behavior fits a pattern researchers have seen in nesting birds.
When I see a bluebird bring in a spider, I think about that hidden value. The prey looks small to us, but it may be an important part of a chick’s early diet.
Why Bluebirds Feed Spiders During Nesting Season
A nesting bluebird has to make many feeding trips. Each trip counts.
A spider can be a useful food item because it gives the chick a compact meal. It is also the right size for carrying back to the nest box. The adult can grab it, fly with it, and deliver it quickly.
That matters in a busy yard during breeding season. I have three nesting boxes set up for bluebirds in my 2-acre Arkansas yard. Even with three boxes, I usually only have one nesting pair at a time because bluebirds can be territorial while nesting.
I never know which box they will choose. Some years, I get lucky and see two broods. Bluebirds can have up to three broods, but I have only had two in my boxes.
After each brood leaves, I clean out the nesting box. Sometimes the pair builds a second nest on top of the first one. Other times, they move to another box.
I often wonder whether the same bluebirds return to my yard each year. What I do know is that the nesting season brings a steady routine of feeding, guarding, and quick trips back to the box.
This spider was part of that routine.
Photographing a Bluebird Carrying Spider Prey
I photographed this female Eastern Bluebird from inside my pickup truck. The birds are used to my vehicle, so it works well as a blind.
I rested my camera on a bean bag over the open window. That gave me a steady support without stepping out and disturbing the bird.
Camera Settings:
- Camera: Canon EOS 7D Mark II
- Lens: Canon EF 100-400mm f/4.5-5.6L IS II
- Mode: Aperture priority
- Shutter speed: 1/250 second
- Aperture: f/5.6
- ISO: 800
With nesting birds, the moment can pass fast. A bluebird may land with food, pause for only a few seconds, then move on.
This female gave me a clear look at the spider before she continued her work. It was a small scene, but it showed how carefully bluebirds provide for their chicks.