Nesting Ferruginous Pygmy-Owls

Ferruginous Pygmy-Owl (Glaucidium brasilianum): Mochuelo común; Brasilsperlingskauz; Chevêchette brune

The Ferruginous Pygmy-Owl was just one highlight of an excellent morning trip to nearby Peralta on the Río Reventazón, which yielded close to 70 different species.

Ferruginous Pygmy-Owl at Peralta: Photo by John Beer

As their name indicates, pygmy owls (genus Glaucidium) are very small birds, about the size of a Social Flycatcher. They are difficult to confuse with larger owls when seen well, but of course this is not often easy to do because of their chiefly nocturnal habits. Nonetheless, it’s worth noting that most pygmy owls hunt their prey, which consists of insects, lizards, and small birds, also by day.

Ferruginous Pygmy-Owl, one of a nesting pair, earlier photo at the same site by John Beer

World-wide there are some 29 Glaucidium species, but Costa Rica is home to only 3 These are the Ferruginous Pygmy-Owl, the Central American Pygmy-Owl, and the Costa Rican Pygmy-Owl.

These would seem to be easy to separate on the basis of range, since maps in the latest bird guides place the Ferruginous (brasilianum) chiefly in the north-west, the Central American (griseiceps) – grey-headed – in the Caribbean lowlands, and the Costa Rican (costaricanum) at higher elevations. However, with the increased coverage by knowledgeable birders in Costa Rica in recent years it is clear that the Ferruginous Pygmy-Owl has now had many confirmed sightings in our own Turrialba area, and even further east.

John and Milena’s recent discovery of a nest site near the Río Reventazón allowed me to be absolutely sure of the identification of this species for perhaps the first time. Plumage is generally not a great help in attempting to distinguish between the 3 resident species, but the Ferruginous Pygmy-Owl has light streaks on the crown, as opposed to the white dots of the other two species. I went back to the nest site with John yesterday morning, where I was delighted to enjoy great close-up views of at least one of the birds,:

Ferruginous Pygmy-Owl keeping an eye on the nest site; photo by John Beer

Another of John’s earlier photos at the actual nest site, which is probably a former woodpecker hole, captures the crown streaks even more clearly.

Ferruginous Pygmy-Owl at Peralta peers out from its nest hole

He and Milena had been able to identify a pair:

The second bird; Ferruginous Pygmy-Owl perched by day against a clear sky; photo by John Beer

I had to make do with just one. But what a little beauty! We were able to stay within close range for at least 40 minutes, as the bird(s) seem very accustomed to nearby human activity. Here’s the last image for today’s post, where the Ferruginous Pygmy-Owl changed his demeanour from totally unperturbed to briefly annoyed:

Go away! Ferruginous Pygmy-Owl at Peralta; photo by John Beer

All 3 of our pygmy-owls can be found in our area, despite the mapping in the bird guides. This is a personal dilemma for me, because my house is located at an around 1300 m elevation on the Turrialba Volcano slope. On the basis of range, voice, and once – at night in January 2010, a good view of a tiny owl with yellow eyes, perched in thick, low foliage in the driveway – I have made 6 different reports of what I concluded is the Costa Rican Pygmy-Owl. Most of these reports were in late 2015 and early 2016, some on successive nights. In retrospect, I now have to admit to doubts. I took no photographs and was able only to give a description of the repetitive, tooting calls, but all 3 species give similar calls! Still, after this Peralta trip I’m now absolutely sure of at least one of Costa Rica’s 3 pygmy-owl species.

By the way, like most places in our area Peralta offers much more than just bird species:

Female Basilisk on a warm rock; photo by John Beer

See our eBird checklist for further details of what else we found at Peralta yesterday morning:

https://ebird.org/camerica/checklist/S90562804

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