Rand Austin L. Social feeding behavior of birds

Chicago: Chicago Natural History Museum, 1954. — 96 p.The associations into which feeding birds enter are many and varied. The simplest are bands of birds brought together by gregariousness; one of the most complex has elements that have earned for it the term "symbiosis." And yet the great diversity is not without order. Surveying the many types of flocking or associations one sees that they can be arranged into series, from simple to complex. Not only that, but the series inter-relate, until rather than a chain or a "tree" we have a whole network or fabric, with analogies in many directions.