the presence of a dump where gulls could feed, and the high fertility of the runway areas. Insects and worm abundance are related to fertility. The de-icing agent -used on runways is urea rather than salt which causes aircraft corrosion ,Urea is also a fertilizer. Thus the runway areas have a high fertility which results in large population of insects and worms. Although the hawkweed makes it difficult for gulls to get at the insects and worms, the worms crawl out from under the protection of the leaves onto the runways during rain or heavy dew. The gulls feed on

these abundant worms, and then

loaf on the warm runways. Chemical control of the worms seemed to be the only feasible solution.

At the Charlottetown airport gulls are the largest problem. The gulls frequent the airport primarily to loaf on the runways which become warm early in the morning. As mentioned, gulls usually prefer to have a good . source reasonably nearby. When the food supply is sufficiently removed, the gulls frequent a new loafing area closer to the food supply. Garbage dumps provide one of the more concen- ' trated and frequented food sources for gulls. Thus the greater the distance between the dump and the airport, the better. Gulls frequenting the East Royalty dump are known to loaf at the Charlottetown airport. Consideration of this relationship is necessary when planning for a new dump site if the hazard of birds at airports is to be minimized.

With the use of knowledge gathered on making airports less favourable for bird populations, the frequency of air strikes in the late l970's was less than that in the early l960's. It is hoped that with further understanding of bird, insect, small manmal and vegetation relationships at airports, it

may be possible to further reduce the instances of collisions between birds and aircrafts.

Bruce Smith 36 Belvedere Avenue Charlottetown, P.E.I.

ANSWERS T0 "BIRD QUIZ"

IDme

l0. ll. l2. is. l4. l5.

Black-capped Chickadee Eastern Wood Pewee

Snow Bunting

Yellow Warbler

Canada Goose

Common Tern

Common Eider

Great Blue Heron Double-crested Cormorant Common Nighthawk

Kestral (Sparrow Hawk) Red-winged Blackbird Ruby-throated Hummingbird, Common Snipe

Horned Lark