That tiny hummingbird you watched flitting in and out of your nasturtiums this past summer has already headed for warmer territory. Here’s the catch: she went east for the winter, not south.
Continent-wide reporting on Internet sites like ebird are taking away the mystery and revealing secrets about where the birds actually go. Some birds migrate west along the mountains, some go east and flock down the Mississippi Valley while others, such as some owls, head north to nest before coming back to Alberta for the winter.
The site “ebird is a place where thousands of birdwatchers can log their bird sightings. There’s a really cool map that allows you to track from day to day where the sightings of different birds happen,” said Geoff Holroyd, chair of the Beaverhills Observatory, located near Tofield, Alberta.
Tracking shows that ruby-throated hummingbirds start to head east in early September towards Saskatoon, Winnipeg and Ontario before they mosey on south towards Georgia and perhaps Florida.
Most Canada geese head more directly south but not all at once. If the weather stays mild, those big honkers will hang around as long as there is no ice on the lakes. Swans will also stay to get the last vegetation from open lakes and ponds, but some ducks, especially mallards may stay around the Edmonton area all winter if they can find open lagoons.
“Waterfowl are tough and can handle cold as long as they can get food,” said Gordon Court, a biologist with Alberta Fish and Wildlife.
Depending upon the severity of the winter, some geese cut their trip short and stay near Calgary, where they glean grain from the fields.
Most insect eaters like song birds and shore birds left in August, Court said because there’s no advantage for them to stay here into the fall.
“Everything about birds’ behaviour is food related. The shore birds, such as the beautiful golden plover and sandpipers you sometimes see at Big Lake and the ruddy turnstone likely left in early August,” he said, adding that herons need open water to fish, and as long as that is available they will stay.
Murder of crows
Crows have been flocking together since August, but they too time their migration according to available food.
“The crows’ spring arrival is synchronized with the emergence of the Richardson’s ground squirrel. In the fall, they start to flock up now and will leave the first week of October,” he said.
Some birds travel enormous distances that span two continents.
“Swainson hawks, which are the hawks you sometimes see on telephone poles, will be in Argentina by November. Black-headed gulls, which you sometimes see on Big Lake, spend their winters in Chile,” Court said.
In addition to Internet postings, biologists use leg banding and even geo-locators to track migrating birds.
Beaverhills Observatory volunteers band baby swallows. They attach geolocators to the birds’ backs and the signals provide important information about these birds, whose populations have declined in recent years. The findings show that tree swallows have a staged southern-migration that begins the first week in July.
“Tree swallows leave one week after the young fledge. They go to the Dakotas for about two months. There is lots of open water and insects there and they moult and get a new set of feathers. We think in September they head along the Mississippi Valley and south again to the Yucatan Peninsula,” Holroyd said.
At this time of year there is also the opportunity to see unusual birds in your own back yard.
“Right now there are northern robins in the area from Alaska. They look a bit different – kind of a bleached robin colour,” said Court, adding the birds will eventually make their way south before wintering in the southern States.
“If we have a mild fall, the migration, especially of the big birds that form the vees, will continue – perhaps for the next two months,” Court said.