Birds migrating in the fall may go as far south as Mexico or even South America. They may start as early as August or as late as November. Southerly migration may be slower because more food is available in northern reaches. Some species take two to three months while others may arrive in less than a month.

Habitats can be unproductive due to wildfires or drought. I did a fair amount of bird photography in the Sierra Nevada mountains in California in the mid to late 1980s. Since that time wildfires have burned much forest. This has left large areas that now have low productive food sources.

Human populations in California have expanded into treed areas removing usable habitat for both native and migratory species. Most birds will survive if they have a wide food base and diversity of food they can utilize.

Northern migration has different dynamics. The birds are driven to breed and set up territories where food and habitat are sufficient to raise young. The move north in spring can be taxing. Some birds lose half their body weight in a short period of time. Females must replace it in order to lay eggs and care for young. Bad weather can prevent food acquisition and nesting season may in turn be upset. Also, some species acquire a mate during migration but most look for a mate after securing a good territory.

Canada and Alaska are prone to massive and unchecked wildfires covering mostly boreal forest land. These areas are slow to regrow because of the cold weather. It may take 50 to 100 years for a tree to reach 15 to 20 feet in height. Biological plagues may wipe out large areas of tree and remove large areas of prior habitat. Strip mining in Alberta destroys vegetation for many decades.

Shorebirds are having nesting problems due to climate change. Large numbers of shorebirds nest in northern Canada and Alaska. If nesting is upset and does not coincide with the hatching and production of mosquito larva, which is dependent on the opening of surface ponds, a problem occurs. If a shorebird chick hatches before the larva eggs hatch it has nothing much to eat and may starve. If the chick hatches two weeks after the mosquito hatch it is often killed by mobs of mosquitos sucking blood from its body, mostly the head area. I have seen one picture of a chick with over a dozen insects perched on its head draining out its blood.

Another culprit in the dilemma is the large amount of permafrost that is disappearing in the nesting areas due to warmer weather. In years past, when the permafrost was present, surface ponds were common. Now with the frost barrier gone this water goes into the ground leaving areas without mosquito ponds.

I have noticed fewer and fewer shorebirds in migration over the last 30 years. I suspect some of this loss comes from the absence of permafrost in the nesting areas. I have talking to bird field biologists from the tundra areas who spent years of research in these areas and they agree that permafrost loss contributes to less success with survival of young shorebirds.

Some people think we should not feed birds, that it makes them reliant on an artificial food source. My opinion is, feed them in late fall, winter and early spring, especially in cold weather periods.

I hate cowbirds and their underhanded way of staying away from parental care of their young. Stop providing millet from May until August when the cowbirds will cease laying eggs in other bird’s nests. Millet is a favorite food, and the female cowbird will produce more eggs with less effort when well fed. Cut off this food source and you will not be supporting this species’ bad behavior.

Habitat corridors are being developed to help migrating song birds. Here birds can find and follow a somewhat continuous line of trees with water present. These are resting areas and also feeding areas. Some work has already been done to ensure a somewhat continuous route for birds migrating mostly to Mexico and further south.