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Predator-Prey

Coyotes Scavenging

Coyote tracks from three different directions led to an area where a deer’s well-cleaned skull was the only remnant of a communal meal. It had been dug up from a spot nearby where it had been cached, and carried to a more protected area to work on.  Coyotes are omnivores, but about 90% of their diet consists of mammals.  Coyote scat I’ve examined has included, among other things, the hair of Muskrat, Snowshoe Hare, White-tailed Deer and small rodents as well as feathers, grass and apples.

Coyotes are commonly blamed whenever there is a decline in the White-tailed Deer population.  Studies involving the removal of deer populations in a given area have not found any evidence that Coyote removal caused an increase in the deer population, nor did it affect the overall deer population growth. The fact that Coyotes are not causing deer populations to decline can also be seen in the devastating effect White-tailed Deer are having on forest ecosystems throughout the eastern United States as the Coyote population increases.

That’s not to say Coyotes don’t hunt deer – they do, primarily in the spring (fawns) and in the winter, especially when there is enough snow and/or crust to slow deer down but not Coyotes. However, much of their venison consumption is a result of their scavenging deer carcasses, which they do any time of year. Examine Coyote scat and the chances are great you will find deer hair in it; chances are also great that it came from a carcass, not a living deer.

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Drama In The Goldenrod Patch

At this time of year when most flowers have gone by, Canada Goldenrod (Solidago canadensis) is a primary source of pollen and nectar for bees, beetles, butterflies, flies and many other insects. Consequently, goldenrod flowers are a popular place for insect-eating predators to linger.

Recently I spied an Ambush Bug that had captured a fly and had its proboscis inserted into it, contentedly sucking away the fly’s innards while I photographed it.  Unbeknownst to me or the Ambush Bug, another predator, a Bald-faced Hornet, had spied the bug with its prey. Although adult hornets consume liquids, usually sugars like the juice of fruits or nectar, their larvae are raised on a diet of insects, so adults are constantly looking for prey. Suddenly, out of nowhere, the hornet flew in, tussled with the Ambush Bug and flew off with the fly in its mandibles, landing on a nearby branch with the object of its thievery.

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Tadpole Maturation

5-22-19 green heron and tadpole _U1A1148The eggs of Wood Frogs, the earliest species of frog to breed in the Northeast, are just hatching and tiny Wood Frog tadpoles can be found swimming about at this time of year. This Green Heron is devouring a tadpole, but it is anything but tiny – certainly not a Wood Frog tadpole. How can this be?

The answer is that the tadpole that the Green Heron caught did not hatch this spring – it hatched last summer. Unlike Wood Frogs and Spring Peepers that mature in roughly two months, Green Frogs and American Bullfrogs can take two or even three years to metamorphose into adult frogs. By their second summer they are of substantial size. The Green Heron has caught a Green Frog or Bullfrog tadpole that has overwintered and would probably have matured this summer.

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Wing Prints In The Snow

2-7-19 gray squirrel kill_U1A2844Rarely have I had the good fortune to come upon a predator dining on its prey, but in this case, luck was with me. Seconds after I spotted a Red-tailed Hawk on the ground working on something it noticed me and flew away, perching within sight so as to keep an eye on its recent kill. This sighting eliminated some of the mystery of the story written in the snow. Wing prints would have revealed that the predator was airborne, and the wingspread might have narrowed the list of potential hawks/owls that it could have been, but determining the species would have been challenging without a sighting.

Although smaller rodents (voles, mice, etc.) make up a greater percentage of a Red-tail’s diet than larger ones, Gray Squirrels (whose remains are visible and were still warm) are consumed. The large numbers of Gray Squirrels on roadsides last fall reflected a booming population which most likely has provided ample food for many predators this winter, including this hawk. Interestingly, fur from the tail had been removed prior to the bird’s directing its attention to the internal organs of the squirrel. A quick retreat by this curious naturalist hopefully allowed the Red-tail to return to its meal.

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Coyotes Investigating Beaver Lodges

1-21-19 beaver lodge img_6186Over the past century beaver trapping has declined and beavers have returned to many of their former habitats. Wolves also have come back in a few areas (not the Northeast yet) — but most places where beavers now live remain free of wolves. As a result, the beaver population has continued to increase, limited only by a few predators, primarily humans and Eastern Coyotes.

Coyotes are major beaver predators and have established themselves throughout the Northeast partly because of the abundance of prey and partly because of the absence of wolves, who keep coyotes out of their habitat. During most of the year, coyotes can take advantage of beavers that leave their pond to feed on land. When they are in their lodges, however, beavers are fairly safe from coyote predation, especially if their lodge is surrounded by water. Come winter, when ponds freeze and beavers remain in their lodges, coyotes can easily approach an inhabited lodge by walking over the ice. Thanks to the lodge’s two to three-foot-thick walls of frozen mud and sticks, the beavers within are safe. (Photo: signs showing a coyote’s attempt to access a beaver lodge)

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A True Mystery Photo

11-2-18 flying squirrel tails_U1A1190A discovery recently brought to my attention has stumped this naturalist.   What you are looking at is a collection of Flying Squirrel tails lying within a 30-square-foot patch of ground adjacent to a stand of Eastern Hemlocks. For several days in succession, additional tails appeared each morning, eventually totaling 20 or more.

Flying Squirrels, both Northern and Southern, are part of many animals’ diet.  Among the documented predators are Great Horned Owls, Barred Owls, Screech Owls, Northern Goshawks, Red-tailed Hawks, Martens, River Otters, Weasels, Fishers, Red Foxes and Bobcat.  Many of these animals can gain access to the trees where the Flying Squirrels reside.  Others take advantage of squirrels foraging on the ground.

The puzzling part of this mystery is the large number of tails.  In cold weather (usually in winter, but we’ve had below-freezing nights recently), Flying Squirrels huddle together in tree cavities in an attempt to provide themselves with added warmth.  Did a foraging Fisher discover a communal den?  How did it manage to capture so many squirrels?  Did the survivors remain in the same cavity, only to be captured in subsequent nights?  So many questions that this naturalist cannot answer. Perhaps a reader can! (Thanks to John Quimby and Michael O’Donnell, who kindly shared their fascinating discovery with me.)

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Some Spiders Still Active

10-29-18 march fly and spider_U1A1162Spiders are ectotherms – warmed and cooled by their environment. In the fall, those outdoor species that remain alive through the winter begin preparing themselves by producing antifreeze proteins that allow their tissues to experience below-freezing temperatures. When a small particle of ice first starts to form, the antifreeze proteins bind to it and prevent the water around it from freezing, thus preventing the growth of an ice crystal. Some species survive in temperatures as low as -5 degrees Celsius.

The pictured hammock spider, still active in late October, is nourishing itself by drinking the dissolved innards of a fall-flying March fly, whose name comes from the predominantly springtime flight period of most March Flies (of the 32 species in the genus Bibio in North America, only three fly in fall).

A common belief is that once cold weather appears, outdoor spiders seek shelter inside houses.  In fact, only about 5% of the spiders you find in your house lived outside before coming into your house, according to Seattle’s Burk Museum.  The reason people tend to notice them more inside may be because sexually mature male spiders become more active in the fall, wandering far and wide in search of mates.

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