These ridges parallel the eagle’s desired route between wintering and breeding grounds. Weathering over a great length of time has left the hard layers (mostly limestone and dolomite) standing as almost straight south-east to north-west trending ridges. Along the front (eastern) ranges the layers are turned up into an almost vertical orientation. The eastern Rockies in Alberta were formed from layers of hard and soft sedimentary rock which were folded and thrust up by great pressure from the south-west. However come prepared for sudden changes.Ī little geology helps to answer this. It was almost as if a dam had burst.įor weather comfort, together with plenty of eagles, we have found early October to be the best time of year – beautiful warm days and beautiful fall colours. Every day the mountains were shrouded by cloud but about noon on their last day the wind shifted, the clouds lifted and that afternoon over 500 Golden Eagles flowed through. Some years ago eagle enthusiasts from Japan came to see the unique migration. At other times our own bad weather is the cause. Very often, perfect migrating conditions at our observation sites produce few sightings because the flow may be blocked by poor conditions elsewhere. We cannot predict when a big movement will take place.
Movement stops as it is getting dark and we often see the birds settling on the peaks. We have found over many years that, in good migrating weather, the movement tends to build up during the morning and reach a maximum in mid afternoon. Migrating Golden Eagles roost on the ridges during the nights and some start moving soon after dawn. Dwindling numbers are seen until early December. The peak migration lasts from mid September until the beginning of November. In the fall some Golden Eagles are seen to return south in late August. The spring migration is over by the end of May. The peak migration period lasts from mid March to the end of April. The first Golden Eagles go north in late February. Our main study efforts have been concentrated at observation sites in the front ranges of the Rocky Mountains of Alberta where one large stream of Golden Eagles passes twice each year.Īnother stream uses geological features along the Rocky Mountain Trench in British Columbia, and some regular observations have started there near Cranbook, BC. The population of Golden Eagles is widely scattered in their wintering and breeding grounds and therefore almost impossible to study.īut along the migration route(s), they pass by in relatively narrow streams and large numbers can be observed. to as far south as northern Mexico) to breeding grounds in Alaska and Yukon. Each spring large numbers of Golden Eagles fly from their wintering grounds (the mountain states of western U.S.A.
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