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Animal Communication

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.

Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.


Clean Antennae Necessary for Sensory Perception

8-9-13 conehead katydid cleaning antenna 098Insect antennae are among the most sensitive and selective chemical-sensing organs in the animal kingdom. They detect information crucial to an insect’s survival, including odors, sounds, humidity, changes in water vapor concentration and air speed. Antennae are capable of these feats because of the sensory receptors covering them which bind to free-floating molecules. Experiments with cockroaches, ants and flies confirm that insects engage in antennal grooming — removing foreign materials from the surface of their antennae with their mandibles — primarily to maintain acute olfactory reception. Pheromones, chemical signals that are vital to insect communication, are used to convey alarm, attract a mate, mark territory and lay out trails, among other things, and clean antennae enhance these messages. (Photo is of a Sword-bearing Conehead Katydid cleaning its antenna.)

Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.


Black Bear Mating Sign

5-30-13 black bear mating sign by A. Balch 002 (2)We’re approaching the peak of the black bear mating season in late May and June, and there’s no better time to look for bear sign than right now. Both male and female bears increase their movements during this time of year. According to the North American Bear Center, males have mating ranges 10-15 miles in diameter and each mating range contains 7-15 female territories. During May and June, both sexes, but particularly the males, mark their territory by leaving their scent on trees, shrubs, telephone poles, sign posts, etc. They do so by thrashing around, rubbing their shoulders and neck against trees and poles, biting and clawing them and urinating on young trees and bushes that they straddle as they walk along. Often the tops and many branches of saplings are broken off, as is evident in this photograph taken recently by Alfred Balch of Lyme, NH.


Beaver Scent Mounds

4-30-13 beaver scent moundsThis is the time of year when two-year-old beavers leave their lodges and strike out on their own, primarily because the woods surrounding a pond usually can’t support more than one family of beavers. Beavers are exceptionally territorial; once they’ve established a lodge, they do not take kindly to interlopers. In order to make this perfectly clear to house-hunting young beavers, in the spring resident beavers build what are called scent mounds — piles (up to three feet in height, but usually much smaller) of mud, leaves and pond-bottom debris — around the perimeter of their territory. They then smear castoreum, a substance that comes from their castor sacs, over the mound. Chemicals in the castoreum convey to roaming young beavers that this particular pond is spoken for.


Frog Vocal Sacs

4-16-13  vocal sacs“Peeps” and “quacks” fill the air these days.  How is it that these frog calls travel so far?  It’s all thanks to a thin membrane , or sac, that most frogs have. Note the single inflated sac of the spring peeper, and the paired sacs on either side of the wood frog’s head. These vocal sacs act as resonating chambers, causing the male frog’s mating call to be amplified and carried far (some species of frogs can be heard over half a mile away). Most frogs have one of three basic types of vocal sacs: a single throat sac (the most common), paired throat sacs (partially separated by connective tissue) and paired lateral sacs (completely separate chambers on either side of the head). Vocal sacs are outpocketings of the floor of the frog’s mouth. When calling, a frog closes its mouth and nostrils, and expels air from its lungs through the larynx and into the vocal sacs. The vibrations of the larynx emit a sound which resonates within the vocal sacs. The frog continues calling as muscles within its body wall force the air back and forth between the lungs and vocal sac. The thickness of the vocal sac wall in frogs varies. Typically, small frogs that call in the air (spring peeper) have thin vocal sac walls, whereas those that call in the water, particularly large species (green and bull frogs) often have thick-walled vocal sacs that appear swollen, not inflated like a balloon, when filled with air.


New Children’s Book by Mary Holland

FerdinandFoxCover PhotoDo you know a 3 – 8 year old who loves animals and would enjoy getting close-up views of the antics of a red fox kit during the first summer of his life? My second children’s book, Ferdinand Fox’s First Summer, has just been published by Sylvan Dell in both hardback and paperback. I have been lucky enough to have had the opportunity to observe and photograph young red foxes as they interact with each other and with their parents. This book consists of a selection of these photographs, accompanied by text and an educational component at the end of the book. Look for Ferdinand Fox’s First Summer in your local bookstore. If they don’t carry it, you would be doing me a huge favor by asking them to. Thank you so much. My next children’s book is on Beavers and will be coming out in the spring of 2014. (I am still looking for a publisher for Naturally Curious Kids!)


Red-winged Blackbird Epaulettes

3-11-13 redwing epaulettes IMG_2348Male red-winged blackbirds have returned to Vermont, and their most notable features are the brightly-colored reddish-orange feathers on their “shoulders”, referred to as epaulettes. In the military, an epaulette is a shoulder ornament that indicates, through its position, color, length and diameter, the bearer’s rank. Some birds, including male redwings, also possess this badge, or visual cue, which indicates the social status of the bird to other birds of the same species. Studies of male red-winged blackbirds and their epaulettes indicate (through dyeing their bright orange/red shoulder patches black) that epaulettes play a significant role in the male’s defense of his territory. Over 60% of the redwings that had their epaulettes dyed black lost their territories to other males. Further research revealed that aggression by a territorial male redwing is proportional to the epaulette size of the encroaching male redwing. It also indicated that male redwings intruding into redwing-occupied territories greatly limit the exposure of their epaulettes by covering them with black feathers. (Female red-winged blackbird plumage is brown and lacks epaulettes.)


Coyote Courtship

2-6-13 coyote in estrus IMG_1583For the past two to three months, coyote courtship has been taking place. Both males and females have been marking more frequently, and male coyotes have been traveling further than usual in search of a mate. A female has marked the top of the stump in the photograph – you can see the foot prints she made as she squatted to urinate. The blood-tinged urine indicates that she is in estrus, or heat. With luck, you might hear the duet of a male and female coyote that is sometimes sung just prior to copulation.


Black-capped Chickadees Celebrate Lengthening Days

1-15-13 black-capped chickadeeEven though black-capped chickadees are named for their chick-a-dee-dee-dee winter song, it is their so-called spring song which resonates most with many of us. It seems as if chickadees are immediately aware of when the days start to get longer, as their mating song begins as early as January. Sounding to some like “fee-bee” and others as “hey-sweetie,” this delightful song consists of two whistles, each about half a second long, with the second whistle a lower pitch than the first. Although these cavity nesters won’t actually be breeding until April, we will continue to be serenaded by their courtship song throughout the winter. As birdsong expert Donald Kroodsma so aptly describes this song, “It is the purest of whistles, this promise of spring.”


A Great Christmas Present!

If you’re looking for a present for someone that will be used year round, year after year, Naturally Curious may just fit the bill.  A relative, a friend, your child’s school teacher – it’s the gift that keeps on giving to both young and old!

One reader wrote, “This is a unique book as far as I know. I have several naturalists’ books covering Vermont and the Northeast, and have seen nothing of this breadth, covered to this depth. So much interesting information about birds, amphibians, mammals, insects, plants. This would be useful to those in the mid-Atlantic, New York, and even wider geographic regions. The author gives a month-by-month look at what’s going on in the natural world, and so much of the information would simply be moved forward or back a month in other regions, but would still be relevant because of the wide overlap of species. Very readable. Couldn’t put it down. I consider myself pretty knowledgeable about the natural world, but there was much that was new to me in this book. I would have loved to have this to use as a text when I was teaching. Suitable for a wide range of ages.”

In a recent email to me a parent wrote, “Naturally Curious is our five year old’s unqualified f-a-v-o-r-I-t-e  book. He spends hours regularly returning to it to study it’s vivid pictures and have us read to him about all the different creatures. It is a ‘must have’ for any family with children living in New England…or for anyone that simply shares a love of the outdoors.”

I am a firm believer in fostering a love of nature in young children – the younger the better — but I admit that when I wrote Naturally Curious, I was writing it with adults in mind. It delights me no end to know that children don’t even need a grown-up middleman to enjoy it!


Rub-urination

On the inside of the hind legs of all white-tailed deer are glands called tarsal glands.  They consist of a tuft of long hairs coming from an area of skin in which are located glands that secrete a fatty substance.  This fatty substance adheres to the long hairs.  When deer urinate, they often assume a crouched posture, causing their urine to run over these hairs.  The lipid, or fatty material, on the hairs causes some of the urine that runs over them to remain there. Excess urine is licked off by the deer. The combination of fatty material and urine gives the glands a unique smell (not the typical deer urine smell.) During the breeding season mature bucks urinate on the tarsal gland much more frequently, and don’t lick off the excess urine, which creates a distinctive rutting odor .  This practice is referred to as “rub-urination.”  All deer urinate on these glands throughout the year.


North American River Otter Roll

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In addition to their winter slides in the snow, river otters leave distinctive signs year round.  Their scat is unlike most other animal scat in that it has little form and often disintegrates into a pile of fish scales.  Sometimes river otters create what are called “rolls” –  areas near water that they repeatedly visit to defecate, urinate and roll around on the ground.  If used frequently enough, rolls become so acidic that they turn black with dying vegetation.  Being a member of the Weasel family, otters possess oil glands and waterproof their fur with oil. It’s possible that in addition to marking territory at a roll, they are distributing this oil throughout their coat when they are rolling on the ground.


Spring Peepers Still Calling

Although Spring Peepers emerged from hibernation about two months ago, on warm nights the males are still advertising for mates and will continue to do so into June. Let your ears guide you to the peepers as they call repeatedly, often while perched on low vegetation near water. Armed with a flashlight, look for the movement of their vocal sacs as they inflate and deflate as the peepers sing. 


Yellow-bellied Sapsucker Drum Roll

The welcome sound of the “Morse Code woodpecker” is once again reverberating through our woodlands.  Although many woodpeckers drum against hard surfaces with their bills, yellow-bellied sapsucker drums are distinctive — they usually begin with several rapidly repeated strikes in an “introductory roll” followed by a pause, then more strikes in an irregular pattern which some people liken to the Morse Code.  These birds, like most woodpeckers, communicate with each other by drumming on different surfaces – often dead snags, but also metal signs and roof tops.  They communicate over long distances, so the louder the drum, the better.  Males are arriving back on their breeding grounds and establishing territories with the help of this drumming before the females arrive.  Females arrive back about a week later than males, at which point, drumming will assist male sapsuckers in obtaining a mate.  Females also drum, but less frequently, more softly and for shorter periods of time. Photo is of an adult female yellow-bellied sapsucker.


Wood Frogs Arrive at Vernal Pools

After noticing the sudden loud clacking chorus at a nearby temporary woodland vernal pool, I went down to investigate, and there were dozens of wood frogs floating on the surface, as they croaked their duck-like quacks in the hopes of attracting female wood frogs.  As far as I could determine, they were out of luck on this, their first day at the breeding pool, as I don’t believe the females have arrived yet.  One clue was the relatively small size of the floating frogs and it seemed as though every frog was calling (only males call).  Plus, time after time a wood frog would swim up to another wood frog and attempt to grasp it only to have the object of its desire utter a “release” chirp (a call made only when a male clasps another male) and swim rapidly away. 

 


Spring Peepers Calling

I heard my first peeper on March 18th, roughly two weeks earlier than in past years.  These tiny members of the treefrog family begin mating rituals shortly after the end of hibernation. The males gather at small pools by the hundreds. Each male establishes a small territory and begins calling the familiar high-pitched “peep” quite frequently. The louder and faster he peeps, the better his chances are of attracting a receptive female. Males usually compete in trios, and the male with the lowest-pitched call usually starts the vocal competition.  If you look closely at the peeper in the photograph you can see some snow fleas hitching a ride.  


Porcupines and Hollow Tree Dens

Porcupines leave plenty of signs where they have eaten the inner bark, or cambium layer, of a tree. Bark is missing on the trunk of the tree, leaving fresh, yellow wood exposed, which often bears incisor marks.  An observation I have made over the years is that porcupines often de-bark around or near their hollow tree dens.  Typically, if a tree den is used year after year, they gnaw off bark each year, sometimes eating the old, scarred portion which, due to previous chewing, lacks cambium cells. This has led me to wonder whether fresh de-barking in the vicinity of their tree den entrance might have more, or as much, to do with a  porcupine’s staking out a claim on that tree than with its sustenance.  I have never come across any research that even mentions this phenomenon, and would welcome feedback from anyone who has.


Mating Season for Eastern Coyotes

If the increased yelping of eastern coyotes hasn’t caught your attention, you may not be aware that this is the peak of their breeding season. Female coyotes come into estrus once a year, for a period of about 10 days.  For the past two or three months, working up to this, male and female coyotes have been increasing their scent marking.  Occasionally you can find where a female has marked with urine, leaving behind a spot of blood (see photograph).  Eventually she attracts one or more sexually active males, and mating ensues. Something I’ve never witnessed, but would love to, is the howling duet of a pair of coyotes prior to mating.   

 


Northern Saw-whet Owl

Saw-whet Owl

One night this week I became aware of a series of whistled “toots,” all the same pitch, coming from the adjacent woods. This far-reaching, distinctive call comes from a surprisingly small owl, the Northern Saw-whet — one of our most common owls, whose common name comes from the “skiew” call that is made when it is alarmed. This sound has a resemblance to the whetting of a saw. Although a Saw-whet only weighs about as much as a robin, you would never know it from the volume and carrying power (over 300 yards) of its call. Typically the male calls only during the mating season, in an attempt to attract a female with whom it will mate. The female then selects the nesting cavity, typically a Northern Flicker or Pileated Woodpecker hole, usually in March or April. This pint-sized raptor (weighing less than 3 ounces, and measuring 8 inches in length) feeds mainly on deer mice. Unlike most owls, it does not swallow the mouse whole, but rather tears it in half, leaving the second half for another meal.


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