Saturday, September 28, 2013

Raven Sightings Increase at the Preserve - Also, 2 Garter Snakes Found in a Bush

Sightings of Common Raven at the nature preserve have been on the increase
Over the last 3 years the number of Raven sightings at the nature preserve has been on the increase. I say sightings, but more often its their low pitched croaking call that is heard without anyone getting a glimpse of the bird itself. In New York State, I've always associated the Raven with the Adirondacks and with very large tracks of forest, but that seems to be changing now. In recent decades as forest replaces much of the farm land in the central part of the State, habitat opportunities for the Raven have improved. They also benefit from a reliable supply of carrion that is provided by frequent car/animal collisions. The Ravens are not alone in benefiting from that - vultures, coyotes, crows and many other opportunistic carnivores and omnivores can rely on supplementing their diet with fresh roadkill.
A reliable supply of road-kill helped Turkey Vultures expand their range northward 
Competition for food between Ravens and Vultures may explain the behavior that I witnessed 2 days in a row this week. Turkey Vultures have been in the process of migrating south for the past few weeks. However, lately when they sail over the nature preserve they can count on drawing a response from one or 2 Ravens. The Ravens, though around half the size of the vultures, don't seem to have any trouble escorting their potential competitors to a higher cruising altitude and thereby ushering them along on their migration. Nothing to feed on here, vultures. You just keep moving right along.
A Turkey Vulture soars out of range of the Ravens
Both Ravens return after the Vultures are ushered on their way
The Ravens are remarkably agile in the air - soaring, diving and rolling. After they showed the vultures to the aerial door, the 2 Ravens playfully spared with each other in the air. It was as if they were exhilarated by a job well done.
One raven tucks in its wings and dives into the path of its companion
 Ravens aren't happy about the vultures and this crow is not happy about the ravens
We may not have the ravens at the preserve for too much longer; as our over-wintering population of American Crow increases their presence, the Ravens will more and more become the focus of the crows’ ire. The crows, through sheer weight of numbers are able to effectively escort the Ravens to the periphery of their wintering grounds where they present little competition for food resources.
A large female American Toad perches on a large rock in the middle of a foot trail
At the preserve we’re starting to see the last of the reptiles and amphibians for this season. Soon all will retire to their winter quarters – whether that means burrowing down into the pond mud or retreating underground into a den. For now, many are still quite active as daytime temperatures are reaching up to 70 degrees F.
This Northern Two-lined Salamander was found beneath a rock at a woodland stream
Red Spotted Salamanders are still being found in the old woods
Some of the massive numbers of young toads that hatched at the ponds and emerged from the water in early summer are still being seen daily. In some places, it’s a challenge not to step on them. Red Spotted Salamanders are also fairly common in the old woods – and along the creeks both Slimy Salamander and Two-lined salamanders are still found.

2 Eastern Garter Snakes intertwined in a Honeysuckle Bush
Ever see a snake in a bush? I have a number of times. Usually they are not hunting, but appear to be coiled up and resting – perhaps waiting for the sun’s energy to warm up their cold-blooded bodies. One day this past week, I found 2 Eastern Garter Snakes together “sitting” about 3 feet high in a trail side bush. The 2 were tightly intertwined and at rest. They were not mating, but perhaps the second snake was lured to that unlikely spot by a pheromone trail laid down by the first snake. Probably the intention of the first snake was not to find a mate, but to find a companion that it could leech warmth from. Snakes sometimes do this in order to warm themselves up sufficiently to become active enough to hunt. They tend to do this on days when the sun’s warmth is not able to do the job alone.

It was a little hard to tell which snake head belonged to which snake body

Sunday, September 22, 2013

The Season's Bounty of Wild Foods

American Mountain Ash laden with berries
To a Gray Catbird, Mountain Ash berries taste just fine
The amount of food available to wildlife can vary greatly year to year. Last year at the nature preserve and generally throughout our region, the nut/seed/fruit production of wild plants was quite poor and consequently much of our wildlife had difficulty overwintering – many species didn't even try and instead opted to spend the winter elsewhere.  In fact last winter it was a bit of a challenge to find foraging flocks of chickadees, nuthatches and woodpeckers in our woods – there was just too little food for them to find.
Wild Grapes provide food for woodpeckers, thrushes and even foxes
This year's crop of beech nuts is not huge but it's noticeably larger than last year's
What a difference a year makes. This fall the woods and pastures are pretty much teeming with wild foods. Most obvious are the apples, butternuts, grapes and maple seeds, but there are many other edible resources just waiting to be eaten or stored. Some of them will not last into the winter – they are just too popular. For instance, dogwood berries go particularly fast, while berries of the viburnums tend to be less preferred. The rate at which the berries disappear has much to do with their fat content; those that contain a relatively high amount of fat are unlikely to last, while those with less fat may remain on the plant long into the winter.
Before migrating, the Brown Thrasher fills up on wild berries
Berries from Silky Dogwood never last long
The Nannyberry's fruit tends to remain on the bush for a long while
Cranberry Viburnum berries also tend to last  well into the winter
I noticed that for the first time in a few years our Virginia Creeper vines have produced a crop of berries. Those berries also seemed to be going fast. The other day I noticed a few migrant songbirds stopping to have their fill of the small grape-like fruits. One parent Red-eyed Vireo had its adult-sized offspring in tow. The younger bird was fully capable of foraging for himself, but he knew that his raspy begging call was still capable of getting a parent to serve up another berry or perhaps an inch worm.
Rose hips from Multi-flora Rose are often a food of last resort for birds
Choke Cherries are popular - though not as popular as wild Black Cherries
Invasive silverberry bushes are newly arrived in our area - we shall see if their fruit is popular
The wild food supply is as important to migrating birds as it is to those that overwinter. Migrants need to pack on the calories in a big hurry in order to fuel their long journeys south. Luckily for them, as we make the transition from summer to autumn there are still lots of active insects, so they can take advantage of that food resource as well.
A crumpled Yellow Birch catkin reveals many small edible seeds
Seeds from Box Elder and other species of maple tree provide excellent food 
Ash seeds are popular with Rose-breasted Grosbeaks and other finches
Every late summer we do an assessment of the nature preserve’s food supplies in order to predict what species of birds are other animals may be able to spend the winter. This year we are apt to play host to a large number of robins and waxwings. They can sustain themselves primarily on wild grapes and the berries of American Mountain Ash, viburnum and Buckthorn. Seeds of maple, ash and birch will be utilized by foraging chickadee/woodpecker flocks. Woodpeckers, Blue Jays and Turkeys will also reap great benefits from the season’s ample crop of beechnuts and hickory nuts. The Jay may eat some beech nuts on site, but many will be stored in dozens of individual cache sites around the forest.
Bitternut Hickory nuts are very plentiful this year
A hazelnut partially removed from its leafy sheath
American Chestnuts are beginning to drop out of their large spiny sheaths
The Burr Oak acorn has a very large cap which covers nearly the entire nut
This has been the finest year for wild apple production in some time
Hawthorn apples or "thorn apples" are about the size of crab-apples 
A consequence of a decent wild food production year will not just mean an increase in fruit and seed eating wildlife populations. A spike in Chipmunk and other small rodent numbers will be welcomed news to scores of predator species including hawks, owls, fishers and foxes.
Don't mind the crumbs, a Red Squirrel likes to eat his butternuts on this bench
The White Spruce trees in our reforestation fields are covered with pinecones
Finches and the Red-breasted Nuthatches will take advantage of the pine seeds

Saturday, September 14, 2013

Monarch Migration - No; Green Darner Migration - Yes!

A migrant male Monarch Butterfly - a rare sight this summer
Monarch Butterfly migration was a complete bust this season. My unofficial count for Monarchs flying through the nature preserve so far is around 4 individuals total. By contrast last year was amazing - thousands of the iconic species passed through during the late season peak bloom of goldenrod and asters. Of course, though an individual Monarch will make the epic journey to Mexico, it takes a number of generations for its descendants to repopulate the northern parts of its range.
A massive bloom of Asters and Goldenrod help fuel the Monarch's long journey

A lack of Monarchs this year shows that there are potentially serious problems on the breeding grounds in the US and Canada and/or on their wintering grounds in Mexico. Deforestation on their crucial wintering grounds is likely the main cause of their decline, but an increasing use of genetically modified crops in the US is being pointed to as  another significant factor. As herbicide tolerant crops can now be doused with herbicides like "Roundup", vital milkweed stands are disappearing - and with them the Monarch's livelihood.
Monarch caterpillar on a Milkweed seed pod in 2012 - we found no caterpillars in 2013
Milkweed is popular with other insects like this Swamp Milkweed Leaf Beetle
Milkweed Tussock Moth Caterpillars also munch on milkweed 
A migrant Green Darner Dragonfly perches along a meadow trail
While Monarch numbers have been low this year, the number of migrant Green Darner Dragonflies has been up sharply – and yes, the Green Darners do migrate. Around a dozen species of Dragonfly migrate in the US. That's especially interesting considering that less than 50 species out of over 5,000 species of dragonfly in the world are known to migrate.
Dozens of Green Darners perched alongside the meadow trails
The dragonflies were zigzagging back and forth over the trail  catching prey
At the nature preserve, on several trails that pass through large meadows, Green Darners line the sides of the trail and take to the air when someone walks too close. The darners blend in so well with the vegetation that it’s really difficult to pick one out until it takes flight. Given that, it was somewhat frustrating trying to get pictures of them as they perched. The swarm of darners flying over the field was also also hard to photograph. There were at least 50 of them zooming back and forth all over the meadow, scooping up smaller flying insects on the wing.
The female Green Darner lays eggs into the water while the male clasps her neck
A shed dragonfly nymph exoskeleton still hangs onto a leaf  
I know that the 2013 breeding season was excellent for dragonflies locally, but a healthy number of migrants tell us that they also did well on breeding grounds in the Adirondacks and Canada. This year, the early part of the breeding season was particularly wet in parts of the Northeast, and so it makes sense that these wetland dependent insects would've fared well. Pools of water that are rich in insect larvae (including mosquito larvae), but not rich in predatory fish are ideal for dragonfly larvae to develop in.
A Green Darner is more slow to take off on a cool morning
Other dragonfly species like this Black Saddlebags were seen with the darners
Meanwhile, Red Saddlebags were still breeding at the Frog Pond
Dragonfly migration is very similar to bird migration. Just like most migrant birds, the dragonflies don’t make their entire journey in one “bound”, instead they utilize migratory stop-over sites. Apparently our habitat-rich nature preserve is one such site – at least it is this year. Since the dragonflies use the same migratory flyways that birds do, at some hawk watch sites across the eastern US, this year there should be thousands of Green Darners passing over. It’s thought that American Kestrels especially take advantage of these dragonfly swarms as a source of food to help fuel their own southward migration.