Biology & Natural History

Biology & Natural History

adult-owl-on-postBurrowing owls that breed in Canada are migratory, spending their winters in southern Texas and northern Mexico -- over 3,400 km away! Each spring they arrive back on their Canadian breeding grounds in mid- to late April.

owl-nest-with-manureWhen the owls arrive, they choose a burrow and territory to their liking. Typically the same areas, and even the same burrows, are used as nests year after year -- but not always by the same pair of owls.

 

Even though they don't actually dig their own nests, burrowing owls will bring in nesting material to "spruce the place up". Their choice of nesting material may raise a few eyebrows -- manure! The owls will bring in horse, cow, or buffalo manure (if they can find it) to line their nest chamber and tunnel.

It's thought that the manure acts as an absorbent in heavy rains so the burrow doesn't flood -- but it also provides a nice soft place for the female to lay her eggs!

Did you know . . .
Burrowing owls store their food in their burrows during the spring and early summer (called a cache). One prey cache contained over 200 mice and voles!

 

owl-eggs

The first eggs are usually laid within two weeks of the female's arrival, and the average clutch size is about 9 eggs. During incubation, the female does all of the incubating while her mate does all of the hunting -- not only for himself but for his mate as well!

newly-hatched-chicksAfter the female incubates the eggs for about 28 days, they start to hatch. The chicks are entirely helpless when they first hatch, and depend on their mother for food and warmth.

This is a critical period for the young owls: if there isn't enough food to feed them all, the younger chicks may be killed and fed to their older siblings! While it may seem cruel, this is nature's way of ensuring that at least some of the young owlets survive.chick-at-2-weeks

 

For about the first two weeks, the young chicks will remain inside their nest burrow, under the warmth and protection of their mother. At about 2-3 weeks of age, the young owlets start to explore the world outside their nest burrow for the very first time. At 3-4 weeks, they start to wander away from their nest to explore other burrows in the immediate vicinity. By the time they're 4-5 weeks old, the young owls can fly and begin to hunt things like insects on their own.

 

At about 6 weeks of age, the chicks are considered to have fledged. Even though they are becoming more and more independent from their parents, there are still many dangers for the young owls to face. The first few weeks after fledging is one of the most perilous times for young burrowing owls -- in fact, almost 45% of the chicks that fledge will not live long enough to migrate for the first time.

 juvies-on-burrow

Beginning in September, the owls from Saskatchewan start their long migration to southern Texas and northern Mexico for the winter. Sadly, we can only expect to see 1 in 20 of the chicks born in Saskatchewan ever again. It's not known if they're dying or just dispersing to other areas and not returning to Saskatchewan.