LEAD POISOjSriISiG IN WATERFOWL. 3 



SPECIES OF BIRDS AFFECTED. 



The list of species of birds at present known to have been j)oisoned 

 by eating shot is small, but it will undoubtedly be increased when 

 the facts are better known. In the following brief list all but one 

 species (the canvas-back) are included from personal observations of 

 the writer: 



Mallard (Anas -pldtyrliynclia) . 

 Pintail {Dafila acuta tzitziJioa). 

 Canvas-back {Marila valisneria) . 

 Whistling swan {Olor columhianiis) . 

 Marbled godwit (Limosa fedoa). 



Lead poisoning is a common affection in all these except the 

 marbled godwit. Only one specimen of this bird that had died from 

 eating shot has been examined. In this species and in other shore- 

 birds lead poisoning is probably rare. Geese and several species of 

 ducks in addition to those listed above are said to have been affected 

 in various localities, in particular on Back Bay, Va., but these re- 

 ports have not as yet been investigated. 



As has been stated, the shot secured are taken while feeding. Pin- 

 tails and mallards delight in working in shallow water, where they 

 dig away the mud to a depth of 6 to 18 inches, in search of succulent 

 roots and tubers. In this manner they work over extensive areas, 

 forming " duck holes " from 1 to 15 feet or more in diameter. Swans 

 feed in much the same manner, but, with their long necks, are en- 

 abled to work in deeper water. The canvas-back is a diving species 

 that digs constantly in the bottom mud and frequently feeds at a 

 considerable depth. With all these birds certain quantities of gravel 

 or grit of som^ kind are necessary for the proper grinding, or trit- 

 uration, of food in the gizzard to jD^^t it in proper form for the ex- 

 traction of nutriment. In the mud of marshes and lowland lakes 

 little gravel is present, and to secure this needed element the birds 

 in feeding develop a tendency to swallow any small, hard object 

 they encounter. In this way the shot that have accumulated about 

 shooting points are swallowed one by one. The bird may be several 

 days or even longer in securing a fatal dose or it may pick up a 

 large number of pellets at one time. In either case the shot are 

 held in the gizzard to be slowly ground away, only small particles 

 of lead passing on into the intestine. 



SYMPTOMS OF LEAD POISONING. 



The symptoms of lead poisoning as observed in waterfowl are 

 similar in many ways to those found in mammals. A prominent in- 

 dication of this malady is a paralysis of important muscles, which 

 increases steadily as the ailment progresses. This paralysis seems 

 first to affect the nerves supplying the great pectoral muscles of the 



