Wow, there is a ton of great stuff crammed into one post! An owl somewhat rare for where it’s at, a ton of facts and bio vocabulary, and some neat medical stuff!

This caught my attention as many of you enjoy the ingenuous tape but strategically placed when birds have injuries so they can tug at the tape placed on bits that won’t cause injury to their feathers or actual bandages while the bird still feels it’s picking off what is annoying it. The tail feather brace is something I haven’t seen before, so I wanted to share it, and then saw it came with an awesome writeup as well!

From New Mexico Wildlife Center

The tiny, nocturnal subject of this week’s Creature Feature is the Northern Saw-whet Owl, a species that we don’t often see in our hospital, although we recently admitted 2024’s third patient of this species! These elusive raptors live in forested habitats throughout much of North America, and their complex migratory patterns have been the subject of scientific study for decades.

The name “Saw-whet” comes from one of the vocalizations this species makes, which is said to sound like a metal saw being sharpened on a whetstone. During breeding season, their most common vocalization, primarily uttered by males to attract a mate, is a series of several high-pitched, monotonous hoots that can sometimes be heard from over half a mile away! Northern Saw-whet Owls are a highly nocturnal species, so those calls can be heard overnight, especially a couple hours after sunset.

While this isn’t quite New Mexico’s smallest raptor species, they come pretty close, weighing only about as much as an American Robin on average! Female Northern Saw-whet Owls are a bit larger than males and might bulk up past the 100-gram mark, but that’s still pretty tiny for a bird of prey. Don’t be fooled, though - these owls are formidable predators of mice in particular, adding occasional variety to their diet with a bat or a songbird here and there.

Many birds have fairly routine and predictable migratory habits, but not Northern Saw-whet Owls. Their seasonal movements are irruptive, meaning that in some years, large numbers of them occur at once along a migratory route, and their population is sparser in other years. Irruptions, or high-density migrations, of Northern Saw-whet Owls take place approximately every 4 years, according to data from banding stations across North America.

Adults of this species tend to migrate earlier than juveniles do, although that pattern does not always hold up. But how do we know which birds are how old? When the birds are banded, scientists take a variety of measurements to find out each bird’s sex, age, and other information. just so happens that the feathers of Northern Saw-whet Owls contain pigments called porphyrins, which are unremarkable to the naked human eye but glow bright pink under a black light. Porphyrins fade over time, though, so shining a black light on the underside of an owl’s wing shows us which feathers are faded and at least a year old, and which feathers are brand new and still able to glow. An owl with a full set of glowing feathers is a hatch-year bird with all new feathers, and an owl with a mixture of glowing and faded feathers is a mature adult, having replaced only some of their feathers in their annual molt!

The bird in this photo is current patient number 24-988, who is recovering from a fractured femur and scapula. The owl’s tail feathers are protected by a tail guard, which prevents the feathers from becoming tattered and broken while the bird’s mobility is limited. This photo also shows the fringed edge of one of 24-988’s primary feathers on the left wing! The fringe helps to break up air currents while the bird is in flight, one of the adaptations that creates silent flight.