No. 4.] REPORT OF STATE ORNITHOLOGIST. 395 



as well as swimmer. It searches for food in the shallows and slime of 

 marshes where even the smallest fish is not able to go, yet where mosquito 

 larva3 may abound. It is shallow, quiet water that the mosquito pre- 

 fers, and if the duck likes the mosquito larva, it is often able to get at it 

 Avhen fish cannot reach it. 



On the strength of this testimony from the Pennsylvania commis- 

 sioner of public health it should be profitable to farmers, and others 

 who may own wet, marshy grounds, to raise ducks and let them have 

 the run of such grounds. It would be cheaper than draining and better 

 than oiling, and would improve the comfort and health of the neighbor- 

 hood, besides in most cases returning probably an incidental profit on 

 the ducks. 



It is a well-known fact that wild ducks, particularly the 

 young, and many species of shore birds feed freely on the larvae 

 of mosquitoes. We have been killing off these birds at a rapid 

 rate, and at the same time, as in New Jersey, spending large 

 sums to destroy the mosquitoes. Dr. Gaumer tells us that after 

 the destruction of the herons, egrets and other littoral birds on 

 the coast of Mexico, disease increased among the inhabitants of 

 that low-lying swampy region. 



We have no exact information as to the cause of this in- 

 creased sickness and mortality, but we know that the mosquitoes 

 of those regions carry malarial fevers and yellow fever to the 

 human subject. We know also that wild ducks and shore birds 

 eat vast quantities of mosquito larvae; that herons and wild 

 ducks eat crayfish which destroy the spawn of minnows and 

 other small fish which feed on mosquito larvae. Knowing so 

 much, we may surmise that there is much more unknowm, but 

 it is not difficult to account for the increased sickness on those 

 coasts. 



A Martin Catastrophe. 



Ever since the long, cold, stormy period of June, 1903, which 

 killed off most of the purple martins in Massachusetts, the 

 species has been rare or absent in the breeding season through- 

 out the gTeater part of the State. Their numbers had been in- 

 creasing slowly, however, in Hampden, Worcester, Middlesex, 

 Essex, Norfolk and Plymouth counties, and in the spring of 

 1914 they appeared in several new localities. 



It seemed probable then that by putting up martin houses it 



