Today’s photos come from UC Davis ecologist Susan Harrison. Her narrative is indented, and you can enlarge the slides by clicking on them:
Great Gray Owl Expedition
In late June I had the good fortune to join a field trip in the southern Oregon Cascades led by Harry Fuller. After retiring as an award-winning San Francisco TV journalist, Harry became a self-taught Great Gray Owl (Strix nebulosa) expert and prolific natural-history author and field trip leader. His book on the owls is full of amazing photos, scientific information and stories. One example is the account of a landowner who fed live-trapped voles to a nesting female Great Gray Owl after her mate was killed by a Great Horned Owl (Bubo virginianus). She fledged her young successfully thanks to her hardworking human admirer!
Our first sighting was an owlet who kept trying to expel a pellet:
As nests, Great Grays often use the tops of large broken-off trees, or platform-type nests built by other birds – for example, the owl-containing former Northern Goshawk (Accipiter gentilis) nest that I recently saw in Finland. Man-made nesting platforms like the one above have been a great boon for these owls.
Later we saw one of the owlet’s parents guarding the nest:
Female Great Grays mind the young and only leave the nest to hunt for themselves. Four times a day or more, their mate flies in bringing food for the 1-4 owlets, who are typically of slightly varying ages. Unlike many other birds, these owls will feed their smallest young first.
Listening for prey, this Great Gray seemed unbothered by us:
Small mammals, mainly voles (Microtus), are the Great Gray’s staple diet. It makes little sense for such large birds to fly long distances for such tiny food items. Thus, according to Harry, when you see an adult Great Gray in the summer it’s probably within a few hundred yards of its nest.
Two weeks later, the owlet was out of the nest:
The adult owls were still guarding and feeding it, but not for much longer:
Many of the other birds we saw were likewise occupied with tending their young.
Pileated Woodpecker (Dryocopus pileatus) removing a fecal sac from the nest:
White-Headed Woodpecker (Dryobates albolarvatus) going out on hunting duty:
Williamson’s Sapsucker (Sphyrapicus thyroideus), the first male of this high-elevation species I’ve seen:
Mountain Bluebird (Sialia currucoides) male delivering food to a rocky crevice:
The same bird posing on red volcanic rock:
The mate of the same Mountain Bluebird, also feeding their kids:
Cassin’s Finch (Haemorhous cassinii), a high-elevation cousin of the House Finch (Haemorhous mexicanus), gleaning food on a Red Fir (Abies magnifica). Females of this species were nest-building at the same location just a week earlier:
Killdeer (Charadrius vociferus) luring us away from its nest:
Our leader posing with his favorite species: