Sunday, April 7, 2013

On Crows and Coyotes

On of the most intelligent animals on the planet - here looking particularly noble
For most of the winter the nature preserve played host to several hundred crows. The number varied somewhat depending on how much snow cover there was. Pretty much the rule is that whenever the snow covered the area’s fields and hampered the birds’ abilities to find insects or seed, that's when the flocks would resort to our hospitality. At the nature preserve the main attraction for them is our well stocked bird feeders – well, at least they are well stocked until the crows get there.  Normally, they also take advantage of other naturally occurring food sources around the property, but this year there was very little of that to be found. Besides the bird seed, the only other things I would see them feeding on would be the fruit of sumac trees and the dead remains of animals. Scavenging opportunities tend to be limited, but when a carcass is discovered, crows are always ready with utensils in hand.
Crows usually have a lot to say - and they say it with a wide variety of vocalizations
Crows make "cawing" sounds, knocking calls, clucking calls, staccato trills and more
In mid-March when the large winter crow roost in Utica begins to break up and all the crow families return to their home breeding territories, the number that visit our preserve falls precipitously. At this time our own resident pairs become territorial and begin chasing off interloping pairs and un-mated juveniles. Crows have complex social behavior. Pairs will mate for life, and very often they retain one or more young from the previous years’ brood to help with the rearing of the new season's clutch. In this respect they are much like beavers, which also retain juvenile "helpers" for several years.
A Red-winged Blackbird scolds a crow that enters his breeding territory
A pair of family members perched together at the end of the day
Currently, at the preserve we have several resident crow pairs which are currently busy building new nests. We also have some raucous flocks of young adults getting into trouble almost everywhere they turn. They have left on their own accord or have been forced out of their parents’ territories, and they have yet to find mates or establish their own territories. These non-aligned crows will band together and try to eek out a living while enduring being harassed and frequently chased away by the resident pairs.
Crows scatter from the bird-feeder table

Less than a minute later, they're all back
Believe it or not, but some of these unaffiliated youngsters will return home to their parents’ territories once in an while. Individuals have even been documented as making regular weekly visits back home. However, most will be welcomed back for a short stay only, and then it's back to the young flock of hooligans. Eventually, these young adults will find mates and establish territories of their own, but by then the flock of outcasts will be infused with a new generation of the unaligned and the chased.
Some Crows gathered at a deer carcass
Coyotes feed on the carcass primarily at night
Last month a young deer died on the property and its carcass elicited a lot of activity from the crows during the day, and a group of coyotes at night. I mounted the trail camera at the scene, and was able to capture ‘round the clock feasting for about an entire 24 hour period. After that there was little left of the carcass, but even so it continued to be visited by a variety of interested parties.
A coyote remained at the site for around an hour after sun-up
The Coyotes return a few days later during a snow storm, but there's not much left of the deer
A group of 3 coyotes spent a lot of time at the carcass. The deer had died beneath a tangle of low trees and brambles, and so one of the coyotes decided to drag it over to an open area a few yards away. She did this by first biting through some intervening branches – this cleared the path and made the job of dragging easier. For a while the 3 coyotes fed together on the deer, but they didn't remain for long once the sun came up. In the early morning, the crows returned to begin the scavenger day-shift.
The bob-tailed Raccoon walks by the remains of the carcass, but doesn't stop

Sunday, March 31, 2013

Bluebird Boxes Offer insight Into Bird Behavior


The male Bluebird checks out one of our Bluebird Boxes

I started to clean out the nature preserve’s Bluebird Boxes last week. The calendar told me it was time to do it, even if the weather didn't quite agree. In fact, there was an impressive snow squall taking place when I did the boxes in our largest field. Despite that, a pair of bluebirds stayed nearby – the male was singing and both birds were checking out one of the boxes only minutes after I had cleaned it.
The female bluebird  warns off a swallow that shows interest in her box
Cleaning boxes probably sounds like a mundane task, but I actually look forward to it. I get to examine the nest designs of well over one hundred bird architects. Primarily, the builders belong to just a handful of species, but individual birds belonging to the same species can have their own unique style.
The male Bluebird preens as the female checks the suitability of a nestbox 
An extremely feathery Tree Swallow nest freshly removed from one of the boxes
Tree Swallow nests are the type most commonly found in our boxes, and these nests are most often decorated with feathers from other birds. Some swallows only make use of a few feathers, while some go all out and use dozens of them. All feathers are not equal to the Tree Swallow – some types are ascribed much greater value. Although they must be difficult to come by, white feathers seem to be especially prized, and it seems as though Tree Swallows must put some considerable effort into obtaining them. The majority of the white feathers that I found in the nest boxes this time belonged to Ruffed Grouse – a bird that incidentally, is not known for its white plumage. The whitish feathers come from the grouse’s underside. 
 
Feathers of Cedar Waxwing, Blue Jay and grouse decorated the nest in this box 
The tip of the Cedar Waxwing feather shows a red waxy projection
So an interesting thing about Tree Swallow nest is how they can help you determine some of the other bird species that are residing in a given area. This time, the feathers of over one dozen bird species were found in the nests, included those of Wood Duck, Cedar Waxwing, Blue Jay, Red-tailed Hawk and Cardinal. Other birds incorporate feathers into their nest designs, but they don’t usually do it with the same panache that characterizes the Tree Swallow’s efforts. House Sparrow and House Wren commonly use nest boxes, and both species will sometimes use feathers. The latter species uses feathers much in the same way it uses twigs – just as building materials and not as decoration or insulation. One of the wren nests I looked at the other day had about a dozen bluebird and cardinal feathers enmeshed in its twiggy support structure. I recall once a Screech Owl that had a similar gaudy collection of feathers on the floor of its nest box, but in that case it was Blue jay and Cardinal feathers. At the time I surmised that feathers came from birds that the owl had eaten.
 
Beneath the Tree Swallow nest was a Bluebird nest with an egg still in it
A House Wren jammed this box completely full of twigs
Often more than one nest will be found in a single box – representing the use and reuse of a box by multiple pairs of birds in a single season. Typically, there would be a Tree Swallow nest or a Bluebird nest on the bottom level, with a Wren nest or a House Sparrow nest build on top of it. In some cases, possible foul play is indicated. In one instance, I suspected that the lower nest was still being used when the new owners came to claim the house. For beneath the Tree Swallow nest, I found a bluebird nest with an egg still in it. Now did the Bluebird abandon the nest before the swallows decided to move in, or were they driven out?
 
Long after young  fledged from this swallow nest, a mouse used it  for a place to cache seeds
This mouse nest was built on top of a Chickadee nest - note the green moss from the Chickadee layer
This mouse nest is made mostly from cattail down and grass
Mouse nests (most often  belonging to the White-footed Mouse), are often found in our Bluebird boxes. The mice move into the boxes in the fall and there they remain to raise at least one brood during the winter. Last winter a large proportion of our boxes held mouse nests, but not this year. This time only 20 or so boxes hosted nests and most of those were  already abandoned by the mice by the time I came by. Whenever I find an active mouse nest, I of course, leave it alone and allow the mice to finish their breeding cycle before removing it. 
This mouse nest is made almost entirely from bitten off pieces of milkweed silk

Sunday, March 24, 2013

Blackbird Fallout and a Rare Yellow-headed Visitor

Our blackbird flocks are composed mostly of Red-winged Blackbirds and Common Grackles

The weather has remained decidedly winter-like in the Northeast, and this is leading returning flocks of blackbirds to remain concentrated in good habitat areas throughout the region. Marshes can be especially good places to find these mixed flocks of Red-winged Blackbirds, Common Grackles and Cowbirds, but nature preserves like ours with bird-feeding stations can also become major blackbird havens.

The flocks very efficiently glean the ground around the bird feeders for edible morsels
At the nature preserve many hundreds of blackbirds have been descending on the bird feeders and to a large degree displacing our usual patrons – including the Cardinals, Mourning Doves and sparrows. The vast majority of the blackbird flock is composed of male Red-winged Blackbirds and that species’ boisterous calls contribute most to the incredible din that the flocks generate. Typically the male Red-wings come north before the females; they do this in order to make an early claim on the best breeding territories.
The blackbirds have somewhat displaced many of our other winter patrons
Blackbird flocks move with a good degree of synchronization, even though their flight formations tends to be looser then that of waxwings or starlings. The blackbird flocks fly low over terrain, and their large flocks can be extremely long – sometimes even stretching from horizon to horizon.
A male Red-winged Blackbird sits upright and starts to show his red wing feathers

Cowbirds make up a smaller proportion of our blackbird flocks
In the early morning, just after the sun rises, the flocks arrive at the preserve and land in the trees around the feeding stations. When all looks safe and secure on the ground, a few brave individuals fly down and start to feed. When it’s clear to all that these pioneers were not snapped up by monsters, the rest begin to descend – but only few dozen at a time, until the entire flock is down and feeding. A feeding flock is intensely skittish, and if any individual in their group gives the signal (which as far as I can determine, is imperceptible to an observer), the flock simultaneously takes flight with a percussive “whoosh” sound. After this they usually gather in the trees above the feeders again, but sometimes the flock will go further, and even leave the general area.
The Common Grackle has an iridescent blue and purple head - hard to see during a snow squall

Some Grackles have a taste for the suet
However, this never lasts long, and soon enough the flock is back in all its glory. The sound of many hundreds of blackbirds simultaneously calling is pretty overwhelming, and to me, it is the first true indication of spring. When there is a break in the weather and when the snow and ice melt on the breeding grounds, these large flocks will break up and the birds will begin staking their territorial claims. But if the winter weather makes a comeback, the flocks are quickly reconstituted and they return to the winter feeding areas. 

A male Yellow-headed Blackbird (a rarity for our region) probes with its bill into the seed husks
At my yard feeders last week we picked a rare visitor out of our own mixed blackbird flock. It was a male Yellow-headed Blackbird – a species that breeds in the far west and winters in Mexico and the extreme southwestern US. This species shows up in the Northeast only by accident. For us, the bird was easy to pick out of the moving flock. Its bright yellow hood and large white wing patch were very distinctive markings, but on the ground, among the throngs of mostly Grackles and Red-wings, the bird was surprisingly difficult to locate. This was due to its feeding behavior. When looking for seeds the Yellow-headed Blackbird would have its face pressed right to the ground – with its beak probing into the snow, and this effectively concealed its yellow front. Also, the bird’s white wing patch is not so evident when it’s not flying or displaying.
The Yellow-headed Blackbird - continuing to feed during an intense snow squall
When feeding the Yellow-headed Blackbird would usually hold its tail high, and at a noticeably more extreme angle than the Red-wings do. So in order to locate the bird, we would look for the one tail that was sticking almost straight up. The Yellow-headed Blackbird remained with us for 2 days, and then a short thaw prompted the flock to move on or disperse. In subsequent days, after winter had reasserted itself, the blackbird flock reassembled at the feeders, but this time there was no Yellow-head in their ranks. Hopefully, he has realized his mistake and is making his way back west.

Sunday, March 17, 2013

The Return of the Resident Geese

Our resident Canada Goose pair - Greta and Felix first nested here in 2005
Birds have begun to return now at the nature preserve – the blackbirds, Killdeer, and even a Woodcock was recently spotted. Our original resident pair of Canada Geese came back early last week and were seen on one of the beaver ponds quite close to their traditional nest site.
Greta does all the incubation, but Felix stands guard much of the time

When Greta leaves the nest to feed, she covers up the eggs with her own down feathers
This pair, named Greta and Felix, first nested here in 2005, and every year since, with the exception of last year, they successfully produced goslings. In 2012 the beavers had raised the level of the pond and the so the birds' favorite nest island was submerged. This compelled the Geese to build their nest in a new and less secure location. 
Greta turns her eggs so they incubate evenly
Hatch day arrived (circa 2011)
Last year, the fallback nest site was located just beneath one of the beaver dams. As I've mentioned before on this blog, beaver dams act like wildlife highways, and it was only a matter of time before some egg-thief came upon the nest. Sure enough, just one day after I discovered where the goose nest was, some predator also found it, and the eggs were pilfered.
7 goslings hatched on the nest island (circa 2008)
Felix leading the brood across the beaver pond
This wasn't the only tragedy that the pair had experienced – in 2007, an enterprising raccoon took advantage of on overhanging tree to reach the nest island and ate or damaged all but 2 of the eggs in the nest. The geese, as formidable as they seem to us, weren't able to drive the masked intruder away and had pretty much given up even trying by the time I got to the scene. I was drawn there by the mournful honking of Greta, as she helplessly watched the raccoon at work. That year the geese only produced 2 goslings, but they managed to raise both of them to the point of fledging.
The unhatched eggs remained in the nest for weeks until some animal finally discovered them (2010)
In 2010 and 2011, Greta produced an entire clutch of eggs – 7 or 8, but in both years only 2 of the eggs hatched. In 2010, after the 2 goslings were able to leave the nest island with their father, Greta kept returning to resume incubating the unhatched eggs. Finally, her duty to help protect the new goslings broke her attachment to the nest and the remaining eggs were abandoned.

Each year in spring, one of our foot trails becomes the "goose trail" once the young birds are ambulatory. At least 4 times a day, the parent geese escort their charge several hundred yards overland between the beaver pond system and the man-made pond. Often in the late spring and early summer, pedestrian traffic will need to stop and pull way off the side of the trail to allow the skittish family to pass by.
Taking the kids on the overland route (circa 2010)
Other pairs of geese have nested at the preserve, and a few have nested somewhere beyond our boundaries, but then traveled here to finish raising their broods. Greta, Felix and their young were always the dominant birds and they would persistently claim the prime feeding areas as well as the best nesting place. Mostly Felix would be responsible for chasing other geese off, but occasionally Greta and goslings would join in.
Just another day of hissing at the beavers 
Felix chases after Julia - who doesn't really offer much of a reaction.
In 2010, the goose family suddenly decided that they loved apple pieces and they started vying with the beavers to get some of theirs. They already were known for hissing and charging at beavers when they swam to close to the goslings, but now competition for apples brought these 2 disparate families into contention even more often. The beavers seemed to be losing the competition –that is until they came up with a great technique to unsettle the geese. I coined this “Goose-tipping” –and it entailed a beaver swimming directly below a goose, and actually making gentle contact with the bird’s feet. This would immediate cause the goose to beat a hasty retreat and thus leave the beavers to enjoy their apples in peace - for a little while, anyway.
The goslings are beginning to molt into adult plumage
Normally when Greta and Felix return in the late winter they bring with them their adult-sized young from the previous season. This was not the case this year because of the nest failure in 2012, but in other years, the yearling geese were tolerated by their parents only until nesting began, and then they would be unceremoniously chased off. However, Felix does seem to be mellowing with age, and he seemed to not be quite as vigilant in his efforts to run off the old kids in the last several years.
Greta & Felix and the rest of the geese that failed to reproduce in 2012 - gathered together for a group picture
With the beaver’s lack of attention to the dam at Morton’s Pond (the first beaver pond), it looks like the old goose island will be well above the water line this season, and ready to once again become the nesting place for our most faithful pair of resident geese.

Sunday, March 10, 2013

Rabbit Friends and Bohemian Fallout

The Rabbit that recently befriended me - and he's not invisible and his name isn't Harvey
Over the years quite a few nature preserve denizens have become acclimated to me  - enough so that they allow a close approach. For whatever reason, few of these have been rabbits. With the notable exception of a Snowshoe Hair that once made a careful inspection of my shoe, the only rabbit that has really befriended me has been an Eastern Cottontail that I call Trés. And yes, he actually likes his name.
Trés' split ear distinguishes him from all others in the hopping crowd
He casually comes right up to me and asks for some sunflower seeds
A few months ago, when Trés first hopped up to me, I thought he was sick, and therefore unlikely to last very long in the predator rich environment of the preserve. I considered bringing him to a wildlife rehabilitator, but after watching his behavior for several days, I determined that his only disorder was excessive friendliness to me (hopefully, this isn't a terminal condition.) In fact, he acted normally in all other respects, and he demonstrated that he was quite capable of running away and concealing himself when he had to.
The Snowshoe Hair that once inspected my boot
The secret to winning Trés' trust was my handy bag of sunflower seed, which I carry primarily for chickadees. Truthfully, I never actively tried to befriend him. No, it just happens that 2 of the fence posts where I regularly leave the seed are in his territory, and so now, just like dozens of his winged compatriots,  he eagerly awaits my arrival, and for me to hand over the treats. 
Just a small portion of the Bohemian Waxwing flock that visited us last week
An amazing flock of Bohemians Waxwings visited the nature preserve several times last week. As the week progressed, their numbers "waxed" until the flock was 350 birds strong. A flock of Bohemians of this size resembles in many ways a flock of European Starlings. The flock’s tight formation assumes a globular shape, which undulates in waves as it moves through the air – and looks almost like a shape-shifting amoeba or a swarm of bees.
These birds show many colorful spots on their wings and tails
From the back, the Bohemian's yellow edged wing feathers create an interesting pattern
Bohemian Waxwings make a distinctive purring trill as they fly – and when the flock is this big, it sounds more like they are sizzling. Many days last week brought strong wind as well as snow and ice. Though 30 mile-per hour winds were enough to ground most of the preserves avian population, it wasn't enough to discourage the Bohemians from taking to the air. In fact they seemed completely unperturbed by whatever the weather dished out. Indeed, even with the high wind they navigated a circuit through the preserve without much difficulty. I guess it's pretty much what you’d expect of birds that only rarely leave the latitudes of the far Northwest, where weather like this is pretty typical.
Underneath their tail is a prominent patch of bright cinnamon  
I resolved to try to get some decent quality video of them. And last week probably represented my best chance, but again I was unsuccessful. The truth is that these birds seemed to be deliberately taunting me! Damn those beauties!! They would be feeding on buckthorn berries in one area – I would set out after them with the better (and much heavier) camera, but when I returned to the spot where they were only minutes before, they would be gone. I’d then see them perched on another distant tree top, but by the time I made it over to them, they’d take flight again and move back another few hundred yards. I wouldn't take this too personally – if it didn't happen so many times!

One day, I deemed it far too windy for me to even try to get close to them with the better camera. Instead, carrying only my tiny camera, I did manage to keep up with the flock as it hopscotched around the preserve. I kept company with them for about an hour while they made the rounds of our (mostly barren) fruit trees. For the most part they were visiting buckthorn trees to partake of that tree’s bitter dark berries. Their mode of operation entailed landing in the crown of a tall tree right above a fruit laden buckthorn – and then, a few birds at a time, they’d descend to the berry tree, until about half the flock was engaged in something like a low intensity feeding frenzy – I mean, they are waxwings and not piranha.
Robins and Cedar Waxwings also partake of the buckthorn berries
There are almost always at least a  few Cedar Waxwings mixed in with the Bohemians
The feeding behavior (as well as the nomadic behavior) of these birds is decidedly finch-like. In fact some birder-folk refer to Bohemian Waxwings as “honorary” finches for this reason. Like crossbills, they sometimes hang upside-down and flutter their wings when they feed on berries, seeds or buds. Their colorful feathers are most on display when feeding in this manner, as the inverted birds flagrantly show off the bright cinnamon colored patches underneath their tails. The bright yellow, red and white markings on their wing feathers are more visible when feeding like this.