Friday, January 20, 2012

Snowy Owls

"Season of the snowies" best describes the winter of 2011/2012. Sightings of snowy owls across the country have occurred in record numbers since the end of November. Snowy owls live in the arctic but wander south outside their normal range ("irrupt") in large numbers somewhat cyclically, usually in search of prey. From the clinic's point of view, however, the 2011 movement of snowy owls was a little different than those experienced in the past. A significant number of snowy owls were admitted to the clinic in 1993, 2000, 2001, 2008 and now again in 2011. This year, they first appeared a month later and a few more adults were seen. The majority of juveniles were admitted in a state of starvation (as has been the case in the past) and the adults sustained traumatic injuries.

In 1993 there were 28 owls, and date of first admission was 10/17; in 2000 there were 17 and first date was 10/26; in 2001 there were 20 and first date 10/19; in 2008 there were 11 and first date 10/29 and in 2011 there were 11, with first date 11/24.

Three juvenile owls remain in the clinic and will spend the next few months with us before it is time to make their journey back north.

Why are record numbers of snowies moving south? Biologists speculate that as with most owl irruptions, prey availability is the root cause. However this time it was not due to a low number of lemmings, small rodents that are snowy owls' staple food source, but instead from a high number present in the spring that resulted in a larger number of owlets surviving to independence. This increase in juvenile owls then put pressure on lemming populations and the birds were "forced" south in search of other food sources. Although predator/prey relationships can be quite complex, the end result in this case was a chance for many people to see a life bird - the magnificent white ghost of the great north. They will most likely begin moving north to their breeding grounds in the spring.

One of our clinic cases is a hatch-year (2011) male. After suffering internal trauma from an unknown cause and a lack of hunting success, some people found it grounded near railroad tracks in Minneapolis without the strength to fly. Upon admission, the bird was malnourished, dehydrated and covered with feather lice. It responded well to treatment for its low condition, and has done well in test flights. It will go through TRC’s pre-release preparation program – intensive exercise therapy to rebuild weekend flight muscles and a refresher in catching live prey – before given the opportunity to return to its arctic home in the spring.

1 comment:

  1. Saw a beautiful snowy in Hastings a few weeks ago -
    such a joy to see in the wild. Thanks for taking care of them!