Aaah, the crisp, cool air of autumn arrived this week! And with it came migrating warblers from northern breeding grounds and a restlessness among the migrants that spend their summers here. Some year ’round birds are still suffering the indignities of the molt, while others are past it and comfortable in their winter colors. A red squirrel with the soft belly of a nursing female scolded me from a tree while I struggled to distinguish one oak tree from another. I think I’m getting it.
A few summer plants bravely sent one or two more blooms out into the cool air while the fall asters still hum with bees. Autumn begins to take hold at Bear Creek.
Winged Migrants Riding through the Night on the North Wind
Standing in a bright, cool morning Tuesday at the weekly bird walk, I learned from Dr. Ben that migratory birds ride the wind that comes with cold fronts. My curiosity piqued, I went to the Cornell Lab site to learn more. Soaring birds, I learned, like hawks or vultures, who use rising warm air (thermals) to get lift for their flight, tend to migrate during the day. However, large numbers of smaller perching birds (passerines) ride the cool, dry, north wind of a cold front during the night to make their flight easier and then settle down during the day to rest and eat.
This week I saw three warblers who’d stopped by on their way from northern breeding grounds. On the weekend, I saw a Nashville Warbler (Oreothlypis ruficapilla). It would have spent the summer raising young in the UP or southern Canada and is now beginning a very long trek to Central America! Since these warblers eats insects, it’ll be on its way quickly to get to warmer areas where insects aren’t in danger of a killing frost.
On Tuesday, after seeing many migratory birds at Charles Ilsley Park on the weekly bird walk, I hurried over to Bear Creek and found some more.
This little bird, that probably flew south on the cold front Monday night, is the Yellow-rumped Warbler (Setophaga coronata). Though it’s not visible in this photo, this migrant has a bright yellow square patch on the top of its tail when it flutters its wings and a yellow blush beneath its wings. In spring, the males are a white, gray and black with yellow patches on their heads and tails. This immature bird was probably born this year somewhere farther north in Michigan or southern Canada. The Yellow-rumped Warblers that stop here can winter farther north than most warblers because they can digest waxy berries that grow in colder areas. So this young bird may be going only as far as Ohio!
In a nearby bush near the southernmost swamp near Snell Road. a Palm Warbler rested from its nighttime ride on the north wind. It too probably came from Canada but will makes its way to Florida or the Caribbean for the winter.
Summer Visitors Prepare for Migration
At the edge of the playground pond, a single Eastern Phoebe (Sayornis phoebe) was stocking up on insects, making quick darts out from its perch. Though it probably raised young here this summer, phoebes don’t hang out with other phoebes, even their mates! This one may be getting ready for its journey to the southeast or Florida; it appears to have finished molting into its winter plumage with a white edge to its tail feathers.
This male Wood Duck (Aix sponsa) is still molting into the eclipse plumage it wears for the winter. It loses its white sides and sharply defined stripes but keeps its colorful eye and bill. Though the Cornell Lab indicates that Wood Ducks can be in southeast Michigan year ’round, I’ve only seen them here during the breeding season. This one’s mate may have nested in a hole in one of the dead trees around the Playground Pond where I saw him – a setting favored by Wood Ducks.
Our old pals, the Mallards (Anas platyrhynchos) start pairing up in the fall, much earlier than most birds. Here’s a male in his eclipse (non-breeding) plumage with his yellow beak, and a female with her orange and black beak, hanging out at the Center Pond. They may be starting to pair bond or perhaps they’re just siblings from the same brood. He’ll change into his familiar iridescent green head before courtship begins later on. Mallards move south for the winter, some going as far as Mexico.
A Local Resident Looking Just Awful!
I also spotted a pitiful sight. A female Northern Cardinal (Cardinalis cardinalis) was huddled in a tree with her head almost bald as she completed her fall molt. Her beautiful brown feathers tinged with red were partially there, but her head looked like that of a small vulture with a huge orange beak! Cardinals go bald during the molt, losing all of their head feathers at once. The photos aren’t great but you’ll get the general effect.
One Tough Mama Defends her Fall Babies
American Red Squirrels(Tamiasciurus hudsonicus) breed twice a year. The second litter comes in late August or September. The babies emerge in 40 days but nurse for 70! This week, I met up with one frazzled mother squirrel. As I was staring up into the tree canopy, trying to study oaks, she suddenly spotted me, came dashing across a log and scooted up a nearby trunk to a sturdy branch. From there, she scolded me soundly for several minutes, continuing even after I took a quick photo and walked away. You can hear a scolding Red Squirrel at this link, though I think the Bear Creek mother, with the soft belly of a nursing female, sounded quite a bit more adamant! Her torn ear and aggressive posture would seem to indicate that she’s no pushover!
A Wild-Looking Fruit and Some Late Bloomers
The native Wild-Cucumber vine (Echinocystis lobata) has finished for the year, leaving behind the dried surface of its weird fruit covered with spikes. It expels its seeds out of the bottom of this fruit and then dies, because it’s an annual. In the summer, you can see its fragrant white flowers covering bushes in the park.
I always like to see a few of the brave summer flowers producing blossoms even as fall settles in. The 6-8 foot native Prairie Dock (Silphium terebinthinaceum) near the benches on the south hill are now mostly bare stalks with giant leaves near the ground – but one stalk still showed two bright yellow flowers about halfway down a stalk.
And at the bottom of the sloping path, a single non-native Chicory (Cichorium intybus) showed its lovely blue color and its pinking shears petals. I think there’s a tiny spider near the center of the blossom.
The yellow centers of the Calico Asters (Symphyotrichum lateriflorum), featured last week, are changing to rose as they age.
And now for those Oaks!
We live, of course, in Oakland Township within Oakland County, so I figure I should learn more about oaks, right?
A couple of weeks ago, I posted a photo of a Bur Oak (Quercus macrocarpa) near Gunn Road and decided I should try to learn more about different kinds of oaks. I’m studying the bark so I can discern them in the winter, but for now, here are 3 leaf types from 3 different kinds of oaks, in case you’d like to put a name to the trees you see. (I always think that a name makes me notice more!)
So here is the leaf of a White Oak (Quercus alba). Notice that the lobes are rounded and the sinuses (spaces between the lobes) are quite noticeable, the lower ones on this leaf reaching about halfway to the center vein. The acorn in this photo may or may not be a White Oak acorn; though it was under the tree, squirrels could have carried it there from Black Oaks nearby. This tree was on the path that winds upward to the park from the Township Hall – a very precious, undisturbed Oak-Hickory forest.
White Oaks grow tall in a forest to reach the light and grow much wider and shorter in the open sun of a field. These beautiful trees with light gray bark can live 200-300 years and according to Wikipedia, one specimen has been documented at 450 years. Imagine the stories they could tell about life in Oakland Township!
The leaves on a Black Oak (Quercus velutina) have pointed lobes tipped with bristles, like other members of the Red Oak group, rather than the rounded ones of the White Oak group. They prefer sandy soils and are a smaller relative of the much larger Red Oak which has a similar leaf but with more lobes and a less shiny surface.
Down at the pond near Gunn Road, I found a sprouting threesome of Swamp White Oak (Quercus bicolor) leaves, probably the result of an acorn being cached by a squirrel in some previous year. It has rounded lobes as part of the White Oak group, like the Bur Oak, but the Swamp Oak’s lobes are shallow and the leaves get broader beyond the middle.
So that’s a start on Oaks, though there’s so much more to know!
If you are available, come with us to the bird walk next Wednesday, October 7, at 8:00 a.m. at Bear Creek. If the weather is right, you may see some lovely little migrants resting and eating before heading south! It’s the season for taking deep breaths of cool air, listening to the last rustle of wind through the leaves before they begin to fall and enjoying the bright white light of the sun as its arc lowers and shortens a bit each day. Each daylight hour in nature becomes more precious now, so try to make the most of them!
*Footnote: My sources for information, as well as Oakland Township Stewardship Manager Dr. Ben VanderWeide, are as follows: Ritland, D. B., & Brower, L. P. (1991). The viceroy butterfly is not a Batesian mimic; 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 beetle info http://www.migrationresearch.org/mbo/id/rbgr.html for migration info, and invaluable wildflower identification from local expert, Maryann Whitman.