THIS WEEK AT BEAR CREEK: Winter Robins, Trailing a Fox and Reminders from Last Spring

Blue morning shadows on center pond

Cam in red winter coat BC
Blog Post and Photos by Cam Mannino

I love the blue shadows that bright sun paints across winter snow. On my visits to Bear Creek this week, I spent some time with my face turned to the ground, trailing animals that had trotted along the paths to the Center Pond, perhaps on the previous moonlit night – or crossed and re-crossed the marsh nearby on a snowy morning. Trundling along, nose down,  I twice caught the sound of social chirping from flocks of birds gathered in trees nearby and went to explore. Later, standing on the ice, I craned my neck skyward to peer at spring reminders hanging from overhead branches. As usual, nature had a few surprises for me. Let’s start with those birds.

Winter Flocks – A Colorful, Noisy Sight

Winter Robins in a tree
Part of a flock of winter robins this week at the park.

Despite the fact that we think of  American Robins (Turdus migratorius) as harbingers of spring, nearly every winter they appear in the bare trees at Bear Creek. According to the Cornell Ornithology Lab, some do migrate, but many robins stay in their breeding  grounds. Evidently they can gather in huge roosts “sometimes including a quarter-million birds during winter.” Wouldn’t that be something to see? This week, a chorus of soft “cluck” sounds alerted me to a small flock of  8-10 birds who were feeding on frozen berries.  Many in this flock seemed to have exceptionally dark heads like this one:

Male robin
Male robin on a wintry day at Bear Creek

Since Cornell says that males have darker heads than females, I think there were probably more males in this group and since winter is not half over and has been fairly mild, perhaps the body feathers from their last molt are still in pretty good shape as well!

Later in the week, I heard another chorus of higher-pitched chipping calls and was expecting to find a flock of Tree Sparrows (Spizella arborea). Instead, I was treated to the rosy heads of male House Finches (Haemorhous mexicanus) socializing with their beige, striped females in bushes along the path just north of the playground. At my home feeder, I only see four or so at a time, but there were again 8-10 in the park, fluttering and moving too quickly for a shot as they hunted for berries. But one male  graciously posed for me in the half shade for a minute.

House finch BC
A male House Finch – his red head in the sunshine, his tail in the shadows.

Readers of the blog know how I love the color red, so I was delighted to see these Robins and Finches brightening up a winter day.

Following Fox Tracks

As I left the playground pond one morning, I came across the round prints of what was probably a Red Fox (Vulpes vulpes fulvus), trotting along the night before,  like this one which passed outside my window at home a couple of years ago.

Red fox on the run
The Red Fox whose tracks I followed this week might have looked like this one, seen at my home.

The tracks are so delicate  – single round circles in a continuous path, as the fox sets its back foot neatly into the track made by its front foot.  Their tracks never wander, as domestic dogs’ do, and they often follow human paths; wild animals, who must find their own food, need to conserve their energy by taking the easiest, most direct route. I decided to follow the fox.  Nose down, I headed west and the fox prints “took me” down the western slope, the neat circles staying close to the middle of the path.

Fox print western slope
Red Fox tracks going down the middle of the path that leads down and up the western slope.

At the end of the path, near the benches at the top of the south hill, the fox turned left and I followed its tracks over the edge of the hill on the path that leads through a tunnel of small trees to the meadow west of the Center Pond. And from there, I followed this ghost fox just past the Center Pond until it turned to go along the boardwalk to the east of the pond.

I turned south to go home because I was half frozen, but I enjoyed spending the last half hour of my walk “accompanying” this wild animal as it had trotted along under a full moon.

Another day this week I found other evidence of  perhaps the same fox. Here are tracks leading again to its exploration of the muskrat lodge in the Center Pond (I’d shown similar tracks in a previous blog). Its tracks clearly stopped by the lodge as it left its “calling card,” a small scat, the size of which was further evidence that this was likely a fox. And then the tracks took their neat bee-line to the other side of the pond (click on photos to enlarge,  hover your cursor over a photo for a caption).

Foxes are one of the predators of muskrats.  In the winter, coyotes and foxes are known to pounce on lodges and feeding platforms to prey on muskrats below. I couldn’t help wondering if that’s what happened in the marsh at the southwestern edge of the forest, where there are two collapsed muskrat feeding platforms from the summer. If so, the attempt wasn’t recent because there was no sign of bloodshed, but a clear path led to the lodge and away. The fox ate no muskrat that night.

Nearby squirrel tracks made a crossroad near the same lodge (see right photo above). One set of prints was much smaller than the other. My guess is that one set is that of The American Red Squirrel (Tamiasciurus hudsonicus); you can hear one there often during the day.  And the other may have been a larger squirrel, probably a black phase/morph of the Gray Squirrel (Sciurus carolinensis), a species commonly seen in the woods around this marsh. They must have crossed the marsh in the morning after the fox’s nocturnal visit. (The Gray Squirrel photo was taken under our feeder as I neglected to get a shot of one at Bear Creek!).

If anyone knows tracks better than I (I am a rank amateur) and wants to correct me on any of these tracks, please feel free!

Memories of Last Spring:  Abandoned Nests

One advantage of following these tracks, too, was that I got a new perspective on two types of nests. Exploring the tracks of the muskrat lodge on the Center Pond, I was able to get a good look at the abandoned nest of the Bald-Faced Hornet (Dolichovespula maculata) that hangs over the eastern edge of the pond. It was a good way to see the amazing tiered construction of this astonishing  insect architecture fashioned from chewed bark and their own saliva.

Closeup hornets nest over ice
The weather has torn away the surface to show us the tiered interior of the amazing nest of  the Bald-Faced Hornet.

Three times this week, I spotted the hanging sack-like nests of the Baltimore Oriole (Icterus galbula), nests I couldn’t see until the austerity of winter revealed them swaying among bare limbs. I love these bright migrating birds who build snug nests that rock their nestlings in the treetops. They won’t be back from Florida and the Caribbean until early May.

oriole BC 5/3/14
A chilly male Baltimore Oriole in early spring.

The first nest I saw (the closeup) was hanging over the marsh at the southwest end of the forest where I saw the collapsed muskrat lodges.  The second was in the trees across the field at the bottom of the Eastern Path.  And the last, very high up, hung near the boardwalk over the marsh on the south end of the Walnut Lane, heading back to the parking lot. Imagine seeing three in one week!

Such a nice reminder that spring will come again!

Sunset at BC
Sunset at Bear Creek – the hour of the fox!

Winter at Bear Creek makes new requirements on us visitors. First of all, the trails and ponds are icy so  Yax Trax or some similar cleats on your shoes/boots are a fine idea. Second, we’re required to listen even more carefully than we do in warm weather. Birds don’t sing now, but do they do call to each other either in pairs or flocks, making it easier to see the few that keep us company in the winter. And sometimes it also requires using our imaginations – to see in the mind’s eye that Red Fox with its brown boots trotting swiftly through the park in the moonlight looking for a meal. Or a Red Squirrel bounding across the ice in the early morning to dig food from its winter cache. Or as in our last few blogs, to imagine the muskrat swimming in the darkness under the ice or the butterfly overwintering in a hollow tree. Then the quiet emptiness of the black-and-white park is filled with activity that we can hear in the treetops or see in our mind’s eye.

*Footnote:  My sources for information are as follows: Ritland, D. B., & Brower, L. P. (1991); Stokes Nature Guides: A Guide to Bird Behavior Volumes 1-3, Allaboutbirds.org, the website of the Cornell Ornithology Lab at Cornell University; Wikipedia; http://www.butterfliesandmoths.org; Herbarium of the University of Michigan at michiganflora.net; various Michigan Field Guides by Stan Tekiela; Butterflies of Michigan Field Guide by Jaret C. Daniels; University of Wisconsin's Bug Lady at www4.uwm.edu/fieldstation/naturalhistory/bugoftheweek/ for insect info http://www.migrationresearch.org/mbo/id/rbgr.html for migration info; invaluable wildflower identification from local expert, Maryann Whitman; experienced birder Ruth Glass, bird walk leader at Stoney Creek Metro Park for bird identification; Birds of North America Online; Audubon.org, Nature in Winter by Donald Stokes, Trees in My Forest by Bernd Heinrich, Winter World by Bernd Heinrich, Savannah River Ecology Lab (Univ of Georgia), Tortoise Trust website www.tortoisetrust.org and other sites as cited in the text.

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