Cowbirds, disease and predators are relatively minor factors affecting bird populations compared to the falling curtain of habitat loss. Environment Canada's 1993 data states that only three percent of Canada's rainforest was undisturbed, while in South America eighty-five percent of rainforest was still standing. Today, it's our turn, as North American conservationists, to keep an eye on the numbers of migratory birds returning from their South and Central American wintering grounds where an unprecedented rate of habitat destruction is occurring. That means less habitat available to support wintering birds and less survivors migrating north in the spring. Yoho's thrushes and warblers are some of the sensitive migratory birds whose numbers will be monitored during ongoing bird counts and breeding surveys in the park.
Birders everywhere can be valuable sources of data.
By keeping a detailed journal of seasonal observations over a long period of time in your area, you will be gathering valuable information about bird populations. Since birds cover such vast areas, they can be barometers for the health of large and complex ecosystems. If a particular population declines, reasons are sought and often valuable information about the environment is gained. We can learn about a buildup of toxic chemicals or about the loss of habitat by simply observing changes in bird populations. Protecting enough habitat is the key to maintaining healthy ecological communities.