In lieu of an abstract, here is a brief excerpt of the content:

t h e t h r e e - m i n u t e o u t d o o r s m a n 212 with the inclination of the magnetic field. This would consistently place the fox at a fixed distance from its prey, allowing it to attack using a highly stereotyped leap.” Daniel Cressey blogged about it this way. “Think of a laser pointer attached to you that always points slightly downwards in the same direction. Now think of some object on the ground. If you walk toward the object until the laser spot is on top of it you know that object is a set distance away.” That is, foxes have an onboard “targeting system” to measure distance to prey and thus increase the accuracy of their mousing attempts. I’m still thrilled by the new things we learn about nature that have been in front of us for centuries. Heck, I even checked to see if I took a northward route to the fridge. However, being directionally challenged, I gave up, being glad I don’t have to sense magnetic north to find the leftovers. 55 how do ground-nesting grouse ever breed successfully? an oily subject Spring and summer are not the favorite times of year for my English setter and my drahthaars. Every day they check me out in the morning when I come down the stairs to see if, by any chance, I’m wearing hunting clothes. After this wardrobe check, when they realize that we’re not going bird hunting, they begin their ritualistic dances that precede their a.m. treat. Gotta love their ability to switch to Plan B and still be your best friend. But I got to thinking about what they’d do if they were afield in the spring or early summer (which is illegal). I’m pretty confident that they don’t miss many birds when they’re hunting. A few molecules of scent from a bird that passes their noses gets their A N I M A L I N T E L L I G E N C E 213 attention, and anything more than a few gets a solid point. So, I’d bet that they could find just about any hen sitting on a nest, be it a Ruffed Grouse, a Sharp-tailed Grouse, a Hungarian Partridge, a woodcock, or a Ring-necked Pheasant. After all, the hen sits for considerable periods, and this has to lead to a good downwind scent cone that surely my dogs would catch. They might miss a rapidly moving bird (like a running pheasant) but surely not a sitting hen. That in fact is why you are not supposed to be out running your dogs during the bird nesting season. Even if they don’t catch a bird, they can disturb it. When undisturbed, most incubating hens leave their nests quietly, skulking away to avoid detection. But a sudden flush could well attract the notice of a predator, who later finds the nest, or the hen wouldn’t have the opportunity to cover the eggs (to conceal and keep them warm). Or am I overestimating my dogs’ ability? It is folklore in some places that hunting dogs cannot find a quail or woodcock hen sitting on a nest. Maybe they just weren’t well trained. But what about coyotes, foxes, and wolves, who depend on their noses for food? Surely they have even better scenting ability than a hunting dog? If so, how could a hen on a nest ever be successful, as during the three-week incubation period, wouldn’t you expect a coyote, raccoon, or fox to at least once cross a scent cone coming from the sitting hen? A bit about the scent cone, which we should know from our dogs. A predator is more likely to encounter a scent cone when it is long and linear. This occurs when airflow is smooth and not turbulent. If air is turbulent and of high velocity, the scent cone is hard to locate, as the scent molecules are dispersed and don’t form a direct line back to the nest. Also a scent cone can be lifted over a predator’s nose by updrafts. Now, if these theoretical ideas are correct, birds can “hide” from olfactory predators by putting their nests where updrafts, turbulence, and faster winds predominate. Another key to hiding from olfactory predators comes from wax or oil. All birds have a gland...

Share