How surely the birds know their enemies! See how the wrens and robins and bluebirds pursueand scold the cat, while they take little or no notice of the dog! Even the swallow will fight the cat, and, relying too confidently upon its powers of flight, sometimes swoops down so near to its enemythat it is caught by a sudden stroke of the cat's paw. The only case I know of in which our smallbirds fail to recognize their enemy is furnished by the shrike; apparently the little birds do not knowthat this modest-colored bird is an assassin. At least, I have never seen them scold or molest him, orutter any outcries at his presence, as they usually do at birds of prey. Probably it is because the shrikeis a rare visitant, and is not found in this part of the country during the nesting season of oursongsters.But the birds have nearly all found out the trick the jay, and when he comes sneaking through thetrees in May and June in quest of eggs, he is quickly exposed and roundly abused. It is amusing tosee the robins hustle him out of the tree which holds their nest. They cry "Thief, thief!" to the top oftheir voices as they charge upon him, and the jay retorts in a voice scarcely less complimentary as hemakes off.The jays have their enemies also, and need to keep an eye on their own eggs. It would beinteresting to know if jays ever rob jays, or crows plunder crows; or is there honor among thieveseven in the feathered tribes? I suspect the jay is often punished by birds which are otherwiseinnocent of nest-robbing. One season I found a jay's nest in a small cedar on the side of a woodedridge. It held five eggs, every one of which had been punctured. Apparently some bird had driven itssharp beak through their shells, with the sole intention of destroying them, for no part of thecontents of the eggs had been removed. It looked like a case of revenge; as if some thrush orwarbler, whose nest had suffered at the hands of the jays, had watched its opportunity, and had inthis way retaliated upon its enemies. An egg for an egg. The jays were lingering near, very demureand silent, and probably ready to join a crusade against nest-robbers.The great bugaboo of the birds is the owl. The owl snatches them from off their roosts at night, and gobbles up their eggs and young in their nests. He is a veritable ogre to them, and his presencefills them with consternation and alarm.One season, to protect my early cherries I placed a large stuffed owl amid the branches of thetree. Such a racket as there instantly began about my grounds is not pleasant to think upon! Theorioles and robins fairly "shrieked out their affright." The news instantly spread in every direction, and apparently every bird in town came to see that owl in the cherry-tree, and every bird took acherry, so that I lost more fruit than if I had left the owl in-doors. With craning necks and horrifiedlooks the birds alighted upon the branches, and between their screams would snatch off a cherry, asif the act was some relief to their outraged feelings.The chirp and chatter of the young of birds which build in concealed or inclosed places, like thewoodpeckers, the house wren, the high-hole, the oriole, is in marked contrast to the silence of thefledglings of most birds that build open and exposed nes