An owlet clings to my shirt after being massed and bled
Two others and I sit among fallen aspens and yellow-flowered cinquefoil, our eyes fixed upwards upon a keyhole-shaped cavity in a snag aspen. In the entrance, a gray blob wiggles. The owlet’s shapelessness reminds me of a potato—fat and elliptical. “He kind of looks like a snowman”, Quintana points out. It’s true, the owlet is a fluffy white ball with a perfectly round head. Suddenly, our fat owlet launches out of the cavity and makes a graceful fall into willows below. After watching for a little over an hour and seeing no action, the owlet’s sudden fledging took us by surprise. We had begun to think all his lurches at the cavity entrance were merely fledging bluffs, that we’d have to wait yet another night to band and bleed this owlet.
Leaving the cavity may be pivotal in an owlet’s journey into the real world but it certainly does not signify independence. For at least four weeks after, the fledglings continue to rely on adults for prey deliveries. In fact, a phenomenon called brood division occurs in which the male and female will become solely responsible for one owlet or, in the case of three owlet broods, a subgroup of two. For example, the eldest will be fed solely by either the male or female after fledging. If the brood consists of two owlets, the youngest (second to fledge) will be fed solely by the remaining parent. In broods of three, two owlets (which may fledge in the same day or very close to each other) form a subgroup, fed solely by one of the parents. Brood division occurs in both altricial and precocial birds*. However, it may be important to note that for precocial birds, shorebirds and gallinaceous species, the adults must focus more on protection than feeding. When precocial birds hatch, they hit the ground running and can feed themselves. Owlets, on the other hand, still rely on a steady supply of moths from mom and dad.
Brood division has its benefits. Because the owlets are separated after fledging they are no longer competing with each other for food. Consequently, their incessant begging is toned down quite a bit and predators are less likely to locate the helpless owlets. Since each parent only concerns itself with feeding part of the brood, foraging may become more efficient. At the same time, the owlets’ sole provider may be teaching them how to forage, teaching them the ropes if you will. These are a few of the speculations concerning the evolutionary benefits of brood division.
Fledging is fine and dandy, but not all owlets survive to fledge. Red squirrels are the primary predators of Flammulated Owl eggs and owlets. This week we drove up to a nest prepared to raise the ladder and briefly remove owlets for massing. We peeped the cavity only to find it empty. After a brief search we located one of our owlets lying limp on a branch high up in a conifer. Red squirrels prefer to eat eggs. When they find a nest of owlets, they may kill the owlets but not eat them after realizing the menu is not quite to their liking. The wild is full of harsh realities; life is a fight for survival.
The remaining two weeks of work will consist primarily of vegetation analysis, “veg” work for short. The Flam Crew will be measuring tree heights and locating the nearest squirrel middens (piles of pine cone scales under a tree) among other things. Linkhart will analyze this information later to help determine what Flammulated Owlets prefer concerning habitat. Despite the importance of veg work, I will miss the nighttime action. I will miss the hoarse hoots of a territorial male Flam nearing a lure net, the shooting stars in a clear night sky seen from ridge tops, and the gentle feel of a helpless downy owlet in the palm of my hand.
Thanks to Dr. Brian Linkhart for allowing me this wonderful and unique experience, the learning opportunity of a lifetime. And thanks to the Flam Crew for teaching the rooky and answering my many questions 😉
*Precocial birds are born with eyes open and can often walk about and feed themselves after hatching. Examples include shorebirds and gamebirds (turkey, grouse, ptarmigan, etc.) Altricial birds, which includes the Flammulated Owl, are born helpless, often naked with eyes closed, and require a great deal of parental care.