6 INCREASE OF THE FOOD Sl'PPLY Xo. 72 



sponge in taking up and retaining moisture. These balls of moss with adhering 

 Lemna should be sent to where they are to be planted as quickly as possible. If 

 they are kept well moistened and have free access of air the plants will keep for 

 some days. The balls of sphagnum can then be thrown on the surface of thfe- 

 stagnant water where it is desired to plant the Lemna. In this way some Lemna 

 taken from Grenadier Pond near Toronto was sent by the writer about the end of 

 May last year and planted on drowned lands near Sudbury. By September the 

 plant had spread well, some of it being found half a mile up stream from where 

 it had been scattered. As the plant floats on the surface of the water and is not 

 anchored in any way, it is easy to see that some of the leaves are likely to stick to 

 the bird when a duck swims in among a bed of this and greedily feeds. When it 

 flies off and alights in the water elsewhere the plant will be detached, and owing to 

 its efficient method of propagation explained further on will become the nucleus 

 of a new growth. There is no reason why all drowned lands should not be made 

 productive of ducks by introducing this plant. 



Another member of this same family is Lemna trisulca, also illustrated. This 

 plant grows wholly submerged; from its peculiar lattice work structure, it might 

 readily be entangled in a duck's feet and transported. It has a rapid growth 

 and is tender and lasts throughout the season. This submerged form is of minor 

 importance to the floating ones. 



FOOD FOUND IN DUCKS. 



In order to ascertain definitely the relative importance of different kinds of 

 food for the different varieties of duck, it is necessary to open and examine a 

 number of birds. The duck's feeding organs are simple and efficient. A tube 

 leads direct from the mouth to the gizzard, which is lined with a very tough skin 

 and surrounded by powerful muscles, and contains fine gravel and coarse sand. 

 As soon as any food enters the gizzard, the muscles start working and the food is 

 quickly cut up between the sand and gravel. For this reason any tender thing 1 

 such as leaves of any kind or soft animal tissue quickly becomes an unrecognizable 

 mass for the ordinary observer and requires an expert botanist and zoologist to 

 identify it. To settle more particularly the relative importance of the different 

 kinds of food, the contents of a number of gizzards of birds killed during the 

 latter part of October on Whitewater Lake were sent by the writer to Mr. Thomson 

 for examination. His results appear below and are worth careful study. Four 

 different varieties of ducks were sent, all of them being deep water feeders. Two 

 of these varieties, the Eluebill and Buffle Head, were shown to be almost exclus- 

 ively vegetable feeders, while the Whistle Wing or American Golden Eye showed 

 more plant than animal food. Of the vegetable matter, the wild celery was most 

 important in two and second in one. Potamogeton Tieteropliyllus appeared in all 

 more or less and evidently is a plant worth cultivating. As explained by Mr. 

 Thomson, at that time of the year, the leaves would not naturally be so important 

 as food and hence the Potamogeton perfoliatus which is valuable mainly for the 

 leaf would not make such a favorable showing. It will be noticed that the seed of 

 the Myriophyllum was an important constituent of the Bluebill's food. The 

 writer could not recommend propagating this plant, however, as he has never 

 found that the ducks eat the leaves and the seeds are only few in number on each 

 plant. It is such a rank grower, moreover, that it would probably choke out more 

 useful plants. In considering the importance of the different plants mentioned as 

 shown by the preference exercised by the ducks, account must be taken of the 



