Northern saw-whet owls are very secretive and sound like a garbage truck backing up. (Matt MacGillivray/Wikimedia Commons)

Northern saw-whet owls are very secretive and sound like a garbage truck backing up. (Matt MacGillivray/Wikimedia Commons)

The Nature Nut

Rosamund Pojar

If you are out at night in the next three to four months, you might hear a sound like the backing-up alarm of a garbage truck. If so, you are probably hearing a tiny, secretive, raptor with a big attitude – the northern saw-whet owl.

The characteristic too too too call was heard in Prince George in the second week of November, although their calls are mainly heard from January to March.

A researcher working in Pennsylvania studying northern saw-whet owls describes them as “tiny brown treasures with brilliant yellow eyes.” Their heads are big compared to their body and their face has been described as “cat-like” (i.e., all eyes).

One of their screechy calls is thought to sound a bit like a saw being sharpened on a whetting stone, hence their name. Even though they are very cute, few people have ever seen one because they are very secretive and highly nocturnal.

Birds of British Columbia does not show many records for our area, yet we always hear them calling on owl surveys.

The Pennsylvania study started because the owls were thought to be endangered and were about to be listed as a candidate for the U.S. endangered species list. However, the study using the play-back method (playing the too too too call of the male) resulted in more than 12,000 saw-whets being caught in mist-nets and banded over 23 years. The project became known as Project Owlnet and it now takes place across Canada, the U.S. and Mexico.

The age of the captured birds was determined by the amount of fluorescence shown by the wings held under UV light. The primary and secondary wing feathers of young birds fluoresce a lot. As the birds get older, there is less and less fluorescence.

Did you know that the wing feathers fluoresce? I didn’t.

An unexpected outcome of this study was that most of the banded birds were females. If they were male, they were mostly juveniles and only one in a thousand was a fully grown male.

Why so few males? Clearly one might expect that using the male call (lure) would attract more females than males, but where are all the males? The full story is yet to be figured out.

Saw-whets, especially the females, migrate south after breeding. It is thought that most of the males may stay in the north over winter and wander about looking for food sources and establishing territories ready for the females coming back north. Due to their secretive nature, we still have a lot to learn about them.

In courtship, males fly around and around the females, full wings exposed. It is thought that maybe the females determine the virility of the males by how much fluorescence they give off.

Part 2 will appear in the Dec. 1 edition of the Interior News