The arrival of spring is noticeably busier at a Northern California horse stable when it comes to bird life. The chatter and activity of birds is everywhere. This stable is located in the urban wildland interface, one of a multitude of horse barns tucked away in the Santa Cruz Mountains surrounded by temperate forests and chaparral.
The abundance of water, sheltered stalls for nesting, and food in the source of feed and insects makes horse stables an appealing place for some wildlife.
Micro Geography of Bird Life at a Horse Stable
A walk through the grounds is an interesting lesson in observing the micro geography of wild birds and how they inhabitant spaces at the horse stable. Within this stable, different species of birds have established distinctive areas for nesting and feeding.
At the entrance to the stable, wild turkey and California (Callipepla californica) quail can be seen passing through. “Gobble, gobble, gobble” alerts the listener to a flock of wild turkeys foraging among the trees.
Wild turkeys (Meleagris gallopavo) are not native to California. These large birds were introduced in the 1870s by the California Fish and Game Commission for hunting. Originally native to the Southwest, wild turkeys are now found in about 25% of the state.
Lower Area of the Stables
Acorn woodpeckers (Melanerpes formicivorus) have staked out the lower arena, flying between their granaries and the nearby oak trees where they roost and set up nests inside tree cavities.
Granaries are where acorn woodpeckers store acorns. Granaries are made up of hundreds or thousands of holes drilled into trees and wooden structures such as utility poles and barns.
Between wooden posts and barns that date back to the 1930s, there are plenty of wooden structures in this area of the stable for the woodpeckers to set up granaries.
Acorn woodpeckers form social groups to establish and defend granaries that can reach 50,000 acorns in size. A group of acorn woodpeckers is known as a bushel. Both male and female acorn woodpeckers have black and white bodies with red caps.
Acorn woodpeckers call “whacka whacka whacka” as they check and move acorns around in their granary. Each acorn is carefully fit to be snug into each hole. As the acorn dries and shrinks, the woodpeckers will move the acorn to a smaller hole.
Wedging acorns into tight spaces helps to prevent theft by jays and other opportunistic birds.
Nearby Steller’s jays (Cyanocitta stelleri) screech noisily as they call to one another from the trees. These jays are the only crested jays west of the Rocky Mountains.
Scrub jays, goldfinches, and rufous sided towhees are also common sightings.
Upper Area of the Stables
The upper area houses most of the stalls and the larger horse arena for riding. The activity of acorn woodpeckers is replaced here by flocks of mostly Brewer’s blackbirds and barn swallows.
Barn swallows (Hirundo rustica) incessantly flit back and forth in the skies over the horse stable in the spring time. Barn swallows are voracious hunters, catching as many as 60 insects per hour and up to 850 a day.
The barn swallows have migrated north for their breeding season from wintering areas in Central and South America.
Known as “leap-frog migration” these barn swallows fly over the year-round resident barn swallows that live in Southern California to arrive in Northern California to set up nests and raise broods.
A recent spring rain leaves muddy puddles that the swallows eagerly visit to scoop up mud for nest building.
The underside of the horse stalls provides shelter and a place to build a nest off the ground and away from predators. The barn swallows hunt and eats horseflies which benefits the horses.
Barn swallows return each year to reuse their nests when possible. Constructing a nest involves over 1,300 trips by both the male and female bar swallows.
Both parents will brood and hunt for food for barn swallow nestlings who fledge between 15 to 27 days old.
While red-winged blackbirds (Agelaius phoeniceus) were sighted earlier in the spring, Brewer’s blackbirds dominate the blackbird population at this horse stable. Brewer’s blackbirds are sometimes confused with grackles but are smaller in size with a shorter tail.
Blackbirds have claimed most of the territory around the main stalls. Horse feed provides easily access to food. Nooks and crannies around the stalls provide plenty of nesting sites protected from aerial predators. Troughs provide a constant source of water for drinking and bathing.
Males blackbirds stand sentry on the top of posts around the upper arena, fluffing feathers and calling.
In a nest built on top of a rake sit blackbird nestlings, waiting for a meal. Nearby, a mother scolds nervously at nearby humans while the male blackbird lands on the nest to deliver an insect.
Overlap in Nesting Sites for Blackbirds and Barn Swallows
The blackbirds and the swallows seem to divide up the rafter space. Stalls either have blackbird nests or swallow nests, never both.
Barn swallows occupy the underside of the horse stalls, building their mud nests and hunting for horse flies. Occasionally, the overlap causes the two bird species to tussle in the air above the horse stall.s
The stalls with blackbird nestlings are evident by the noisy chitter emanating from the stalls. A quieter peep peep peep can be heard from barn swallow nests.
In the stalls that abut chaparral, killdeer make their homes. The name Killdeer is onomatopoeia, meaning that the name of these birds is from the “kill-deer” sound they make.
The shrubs in this area provide plenty of undergrowth to hide away in while the dirt of the stall is home to lots of insects attracted by the horse manure.
Killdeer chicks take advantage of a lull in horses lessons to eagerly enter the empty arena to snatch up insects kicked up by trotting horses.
Killdeer chicks are what is known as precocial. This means that from birth, killdeer chicks are mobile. I once read an apt description of killdeer chicks as “part cotton ball, part ostrich” in reference to their fluffy bodies and ostrich-like legs.
Nearby the mother engages in distraction display by pretending to have a broken wing in order to lure away potential predators while her chicks feed. Female killdeers will run away from their chicks, calling and fanning their wings in an effort to distract predators.
Black Phoebes and House Finches
Black Phoebes and house finches can also be seen in the upper area.
Black phoebes are always found near water and build their nests using mud. The troughs at the stable provides plenty of access of water. Late spring rains create plenty of mud that can be mixed with hay for nest building.
Turkey vultures swoop silently overhead.
The call of a hawk from the nearby trees reminds these birds that despite the peaceful air, danger lurks nearby.
Johnson, T. W. (n.d.). Out my Backdoor: Barn swallows offer unique window into nesting | Department of natural resources division. | Department Of Natural Resources Division. https://georgiawildlife.com/out-my-backdoor-barn-swallows-offer-unique-window-nesting
Starin, D. (2016, March 8). California’s Wild Turkey Troubles. Scientific American Blog Network. https://blogs.scientificamerican.com/guest-blog/california-s-wild-turkey-troubles/