An online resource based on the award-winning nature guide

Animal Communication

The Silent Communication of White-tailed Bucks

9-23-14  antler rub IMG_7310Rising levels of testosterone circulating in a buck’s blood toward the end of summer results in the maturation of antlers and the drying up of the velvet that was providing nutrients to them. It used to be thought that bucks engaged in rubbing their antlers against saplings at this time of year in order to remove the velvet, but research has shown there is much more behind this behavior. Rubs are visual and olfactory sign posts that transmit important information to other bucks and does in the area prior to and during rut, such as individual buck identification, breeding readiness, age and hierarchy.

The positioning of the antlers against a tree is not random — a buck generally rubs the base of his antlers and his forehead skin against the tree. The skin between antlers contains a multitude of scent-producing skin glands called apocrine glands (humans have them and utilize them during emotional sweating). These glands typically are inactive during the summer months, but in response to rising testosterone levels, they become increasingly active in the fall. The most active glands are found in mature dominant bucks.

Thanks to recent studies we know that more rubs are made in years of good acorn production than in poor mast years. Young bucks appear to make fewer rubs than mature bucks, and they tend to start rubbing much later in the fall (so rubs you find now were most likely made by mature bucks). Research suggests that older bucks may be making more than 1200 rubs during the roughly 90-day rubbing period, which comes to about 15 rubs per day.

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Make Way For Ducklings

5-26-14 mallard & ducklings  470After having spent a month or so incubating her eggs, the mallard hen begins to hear her ducklings vocalizing from inside their eggs, roughly 24 hours before they start to hatch. She responds with quiet calls, and begins turning the eggs frequently. Within 36 hours the ducklings crack open (“pip”) their eggs with the help of an egg tooth that is lost soon after they hatch. The down of the ducklings dries within 12 hours and often the morning after her young hatch, the hen leads them to water (not necessarily the closest water to the nest). She encourages them to follow her by quacking up to 200 times a minute as they travel over land to their watery destination. The ducklings can feed on their own, consuming mostly invertebrates and seeds. Once in the water, if the ducklings start to scatter, the mother can be heard repeatedly and softly quacking to her brood to gather them around her. She will continue to provide them with cover and warmth for the next couple of weeks, especially at night and during cold weather.

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White-tailed Deer Pheromone Glands

11-15-13 white-tailed deer glands 582Animals communicate with their own species through strongly scented chemicals known as pheromones. Many mammals have glands that generate pheromones. The messages the scents convey vary according to the pheromone that is used – they can indicate alarm, territorial boundaries, the age of an animal and/or its sex, hierarchy and the receptiveness of an animal during the breeding season, among other things. White-tailed deer have scent glands where you might not expect them – their heads, legs and feet. Their primary glands and their functions are: forehead (scent left on antler rubs and overhanging branches), preorbital (near eye, doe uses it to communicate with fawns), interdigital (between the two toes of each hoof, foul-smelling yellow substance left on the ground with every step a deer takes), nasal (inside nose, may produce a scent, or may just lubricate the nose), preputial (on inside of buck’s penal sheath, function unknown), tarsal (inside of hind legs near middle joint, urinated on to spread scent, used intensely by bucks during rut) and metatarsal (outside of hind legs between ankle and hoof, function, if any, unknown).

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Bruce Spanworms Emerging & Mating

11-7-13 winter moth IMG_4880I try not to repeat post topics, but in the past two days the sudden emergence of inch-long, tan moths in the woods has been so dramatic that I couldn’t not mention them. These ghost-like, light tan moths are referred to by entomologists as Bruce Spanworm moths, Operophtera bruceata, named after an entomologist by the name of Mr. Bruce. They are often called Winter Moths, due to the fact that they are one of the latest moths to be seen flying, as well as Hunter Moths, as they share the woods with hunters at this time of year. From October to December Bruce Spanworm moths emerge, mate and lay eggs. While this timing is unusual, it makes sense when you think about it — many birds, their primary predators, have left for their wintering grounds. All the moths you see in the air are males — females are wingless and cannot fly. The females crawl up the trunk or branch of a tree and send out pheromones to attract winged males. After mating, the female lays eggs which hatch in the spring, and the larvae feed on a wide variety of deciduous leaves, favoring Trembling Aspens, Sugar Maples, American Beeches and willows. Periodic outbreaks of these caterpillars can result in heavy defoliation.

NB: “This is easily confused with Operophtera brumata – Winter Moth, which is an introduced species from Europe and an abundant pest in the Northeast. Also easily confused with Autumnal Moth (Epirrita autumnata).” Kent McFarland


Coyotes Howling

coyote 156Eastern Coyotes are heard with some regularity in New England, especially in the fall. The typical family unit consists of two parents and their young that have yet to disperse (often females). Together these four or five Coyotes serenade us with a very distinctive chorus, often several times a night. One wildlife biologist described this chorus as starting with a few falsetto yips, then blossoming into something resembling maniacal laughter, with the yips stringing together into chattering howls. Coyotes use their voices to communicate with members of their family, as well as with other Coyotes. If the family members have been off hunting by themselves, the howling serves to call the family back together again. The familial chorus also serves as a warning to other Coyotes not to trespass onto their territory. (Unless otherwise noted, my photographs are taken in the wild. This photograph was taken at Squam Lakes Science Center.)

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Thrashing: Moose Rut Sign

10-23-13 moose thrashing sign 051During their breeding season, or rut, bull moose display a number of behaviors that are not commonly seen any other time of year, and many of these behaviors leave obvious signs, including broken branches, scraped bark, wallows and tracks. Bulls roam their home ranges, thrashing their antlers back and forth against shrubbery and saplings while leaving their scent. The sound of their antlers beating against vegetation is thought to signal the bull’s dominance to other males, as well as serve to attract females. The pictured broken balsam fir sapling and its frayed bark are evidence of this behavior.

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Eastern Chipmunks “Clucking”

10-2-13 eastern chipmunkIMG_3035Especially in the fall, and sometimes in the spring, the woods are full of “clucking” Eastern Chipmunks. It’s unusual to hear this call during the summer, but once leaves have started to fall off the trees, giving chipmunks a clearer view of the sky, the chorus begins. One chipmunk starts calling, and the message is passed on to other relatives, who join in. These vocal little rodents are warning each other of the presence of an aerial predator, perhaps a hawk or day-hunting owl. The next time you hear this distinctive alarm call, look skyward. You may well be rewarded with the sight of a raptor flying overhead.

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