Sibley guide to birds pdf

Panama, Greenland, Bermuda and Trinidad sibley guide to birds pdf Tobago. This publication is the official source on the taxonomy of birds found in North and Middle America, including adjacent islands. This page was last edited on 2 December 2017, at 19:58.

This chart and the following text were prepared in 2003. Any updates would be welcome. First, it should be stated that the single most significant threat to bird populations is habitat destruction, in all of its forms and with all of its causes. A chart showing estimated numbers of birds killed annually by each of several different causes. The various causes of mortality outlined below kill individual birds directly, and can certainly have an adverse effect on population size, but can actually have a beneficial effect in some cases. As long as the habitat is intact, the population has the potential to replace the lost birds. In simplest terms, habitat destruction reduces the population by reducing the available resources, denying birds the chance to reproduce, and effectively putting a cap on the population size.

The problems outlined below are serious threats and are implicated in the declines of many species. Millions of houses and buildings, with their billions of windows, pose a significant threat to birds. Simple steps can be taken to reduce the number of birds striking windows. Decals that stick to the glass are not very effective, but strips of tape on the outside of the glass, or strings or feathers hanging outside the window, each no more than 10 inches apart, are fairly effective. Decorative features like stained glass designs or window dividers can achieve the same result.