How do Birds Know When to Migrate?

Many of us wonder how birds know when to migrate and are concerned that if we leave certain feeders out, such as hummingbird feeders, the birds will be encouraged to stay.  This simply isn’t true, so let me tell you how birds that we have enjoyed over the spring and summer months know it’s time to return to their wintering grounds.

Light is the first indication, days are becoming shorter and shadows are lengthening.  Natural food sources are also diminishing, sending the birds further south where it’s more readily available.  Cooler temperatures are starting to creep in indicating a change of season.  Birds’ instincts take in all of these factors which tell them it’s time to leave their breeding grounds and begin the great journey south.

What can you expect to see during the last weeks of September?  Plenty of warblers are flitting through parks, forest edges and meadows.  If you’re planning to scout out these beauties, make sure you take a field guide so you can distinguish between the many species.

Are you curious why blue jays are flying in sizable flocks?  Blue Jays are considered partial migrators travelling no further than a few hundred miles.  Studies have shown the majority who migrate are young with fewer adults.  This doesn’t happen every year, so there’s no rhyme or reason to when they will make this trip again.

Canada Geese are also moving in their familiar V formation.  But wait, they seem like they’re going in the wrong direction.  You’re likely seeing family groups in search of agricultural fields to feed in.  In late summer after their molts are completed and the young are able to fly longer distances, they can be seen flying in any and every direction.  Canada Geese will be seen in larger flocks, going in the right direction, south,  by late October through early November.

Turkey Vultures meander high in the skies in loose groups as they commence on their southern journey.   Many species of hawks have begun their migration.  Substantial numbers of these raptors can be seen at  hawk watches throughout the region.  South of our border at Cape May Point, New Jersey, more than 11,000 sharp-shinned hawks were documented in one day.

This time of year, often referred to as Indian Summer, is an excellent time to hike through conservation areas and local trails.  While enjoying the early fall colours, we are able to take pleasure in the spectacle of migrating birds as they pass through different parts of Ontario.  Take advantage of this beautiful season, grab your binoculars and spend time outdoors taking in the scenery and keeping an eye to the sky!

Happy birding!

By Jane Paradis

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