A female owl looks down 

Climbing the ladder, Photo courtesy of Andy Bankert


“Do you want to climb the ladder?” Sophie, a fellow Flam Crew member, asks me. I have already been out to mass owlets twice, but have not yet had my first try at taking them out of the cavity myself. I jump at the prospect. We lean the ladder against the aspen and I begin the ascent towards the cavity about 20 feet above me. Once at the top, I wiggle my arm into the cavity. The experience reminds me of a game played at Halloween parties in which participants stick their arm into a covered container and guess what they are feeling (spaghetti becomes hair and hard-boiled eggs become eyeballs). Right now, my arm deep in the cavity, I feel fuzzy, wiggling blobs and an occasional gentle nip to my fingers. I also feel something runny and wet. I pull out the three owlets one at a time and place them in a yellow mesh bag. Then I place the bag between my teeth, the owlets giving raspy insect-like calls, and descend.


Flammulated Owls usually have 2 to 3 owlets that hatch asynchronously. The smallest owlet is the last hatched, the runt. We mark the owlet’s heads with different colored markers so we can discern between the chicks as the season progresses. Red is the runt, blue the eldest. After they have hatched, we try to take them out every day and mass them, as well as measure their growing primaries. The increase in weight can be impressive. Over a span of seven days the eldest grew from 28 g to 50 g—that’s a lot of moths!


Flammulated Fuzzball 

Flammulated Owlet at 9-11 days old


One cute owl 

Owlet at 14-16 days 


To reduce stress on the owlets, as well as the female watching nervously nearby, we try to keep our procedures down to ten minutes. After we are done, I gently place the owlets back into the mesh bag and climb back up the ladder. Being extra careful not to drop the squirming fuzz balls, I place each one back into the cavity, which is a little over a foot deep. I catch whiff of a mild odor emanating from the cavity; no doubt the cavity is caked with liquefied moth, the excretions of growing owlets.


We do not mass owlets at every nest, an impossible task. In this case, Dr. Brian Linkhart has chosen one nest from one of the study sites to measure the rapid growth of these diminutive raptors. The owlets occupying this particular nest are predicted to fledge around July 6.