Possible steps in the evolutionary development of bird navigation

Hypotheses are presented to explain the evolutionary development of navigational ability in migratory birds. Areas of discussion to describe the possible techniques are: (1) sun compass, (2) bicoordinate navigation, (3) star compass, (4) wind cues, (5) earth magnetic field, and (6) landscape features. It is concluded that landscape is the single most important cue for orientation of nonmigratory birds. The long range migratory birds appear to use a combination of cues with the relative importance of the cue dependent upon the species of the bird involved

Statement on Acid Rain and Waterfowl

Izaak Walton League of Americaunpublishednot peer reviewedOpe

Nest Houses for Wood Ducks

Ope

Duck Food Plants of the Illinois River Valley

For the past 5 years the necessity for improvement of natural food beds in the Illinois River valley has been apparent

Breeding Populations of Migratory Waterfowl

F33615-84-C-3404; University of Dayton Purchase Order No. R1-43007 issued February 5, 1986Report issued on: issued February 5, 1986INHS Technical Report prepared for unspecified recipien

Duck Populations and Kill: an Evaluation of Some Waterfowl Regulations in Illinois

This paper was conceived and written in an attempt to evaluate the effect of various hunting regulations on the kill of ducks in Illinois, and to ascertain the optimum dates for Illinois hunting seasons of various lengths.  Recent open seasons in Illinois\u27 (1938-1942) have protected blue-winged teals more than any other species.  These open seasons have protected other species in the following descending order: shovelers, green-winged teals, pintails, widgeons, mallards and black ducks, ring-necked ducks, canvasbacks, lesser scaups, ruddy ducks and gadwalls. The dates for the waterfowl hunting season in Illinois should depend upon what species of ducks need the greatest protection, and whether the hunter or the waterfowl population should be favored. Open dates suggested by this study are as follows: For a 30-day season, November 1-30; for a 45-day season, October 22-December 5; for a 60-day season, October 10-December 8; for a 70-day season, October 1-December 9; for an 80-day season, September 26-December 14; for a 100-day season, September 20-December 28

Lead Poisoning as a Mortality Factor in Waterfowl Populations

The mortality resulting from lead poisoning in populations of wild waterfowl has been a cause of concern to conservationists for many years. This concern has grown out of the knowledge that lead poisoning is of common occurrence among waterfowl, that this poisoning results from the ingestion of lead by the birds in their feeding, and that large numbers of lead pellets fired from the guns of hunters lie in lakes and marshes visited by waterfowl. The present paper is devoted primarily to the evaluation of losses resulting from lead poisoning in wild waterfowl populations. The approach toward evaluating the importance of lead poisoning in wild waterfowl was threefold : ( 1 ) appraisal of the incidence and magnitude of waterfowl die-offs resulting from lead poisoning, (2) appraisal of the incidence of ingested lead shot among waterfowl populations in fall and early winter, and (3) appraisal of waterfowl losses resulting from the ingestion of various quantities of lead shot per bird

Proximate and Ultimate Causation of Egg Size and the "Third-Chick Disadvantage" in the Western Gull

This is the publisher's version, also available electronically from http://www.jstor.org/stable/4087093?seq=1#page_scan_tab_contents.No abstract is available for this item

Preferential Rating of Duck Food Plants

An intensive study of the occurrence and use of duck food plants in the Illinois River valley was conducted 1938-1940. A preliminary report covering the results of the 1938 investigation was issued (Bellrose and Anderson, 1940). Altered water levels in 1939 and 1940 greatly changed the food resources of many bottomland lakes through the development of extensive communities of moist-soil plants.  This paper summarizes the data for 1938-1940.&nbsp

An Abbreviated Review of Lead Poisoning in Waterfowl

Ope