Muskegon Lake Banding, November 15

Yesterday at the Muskegon Lake Nature Preserve banding station, I had several interesting captures and sightings. Most notable was a flock of 44 Bohemian Waxwings - my first for the preserve. The skittish group sampled some highbush cranberries then quickly departed. Common Redpolls, a lone Purple Finch, Carolina Wrens, and a slightly tardy Ruby-crowned Kinglet prompts me to comment further.

Of the nine species of finches that typically occur in Muskegon County, four (American Goldfinch, House Finch, Purple Finch, and Pine Siskin) exhibit more typical migration patterns. The others (Pine Grosbeak, Red Crossbill, White-winged Crossbill, Common Redpoll, Evening Grosbeak) are considerably less regular in abundance and timing. These species may be abundant some years and absent in others, and their visits are not entirely restricted to the winter. However, even during irruption years, Pine and Evening Grosbeaks have been consistently scarce since the 1980's. Though typically rare, White-winged Crossbills likely breed in the county on occasion. Last spring, I had a group of them frequenting a grove of Norway Spruce near my house at least until late May. However, I was not able to confirm actual nesting.

In Muskegon County during the fall, Pine Siskins and Purple Finches generally migrate between early October and late November. Spring passage peaks in early April. When they irrupt, Pine Siskins may appear in moderate to large quantities during the winter and sometimes persist in small numbers into the summer. Less common, Purple Finches can also be found in this area during the entire year, but they are rare during the summer.

During typical incursions, Common Redpolls arrive in early November and depart in mid March. At Muskegon Lake Nature Preserve, a flock has been present daily since November 7. Yesterday, an adult female blundered into one of the nets (pictured center). Redpolls demonstrate remarkable variation in streaking and in the amount of red in their plumage. Adult males have much red in their face and chest, but young females typically show none at all. Two extremes, birds that I banded last winter, are shown to the left and right. Such variability should be considered when assessing a potential Hoary Redpoll, which are exceedingly rare in lower Michigan. Local banding records indicate that less than 1 of 1,000 redpolls is likely to be a Hoary.

As measured by mass, the eight smallest species of birds that occur in Muskegon County are: Ruby-throated Hummingbird, Golden-crowned Kinglet, Ruby-crowned Kinglet, Brown Creeper, Wilson's Warbler, American Redstart, Northern Parula, and Magnolia Warbler. Despite their small body-to-mass ratio (which accelerates heat loss), three of these species are actually more frequent here during the colder months. Golden-crowned Kinglets (GCKI) arrive in late September and do not depart until late April. Fairly common during the winter, they prefer habitats that provide thick evergreens (especially hemlock) for roosting. Breeding is very rare south of the northern Lower Peninsula, but this summer I did have a couple territorial males at Duck Lake State Park.

Ruby-crowned Kinglets (RCKI) also arrive in late September, but they continue southward, and they have typically vacated by mid-November. I have never found one during the winter in Muskegon County (and considering the similarity in names and general appearance, at least some of the records from past Christmas Bird Counts are definitely erroneous). Locally, spring migration extends from early April to mid May. Since the species breeds in spruce swamps and is generally uncommon even in the Upper Peninsula, summer records are not to be expected from the Muskegon area.

Aside from their head feathering, the two species are quite similar in plumage, shape, and size (song and calls are very different). Golden-crowned Kinglets are smaller, but male GCKI are equivalent to female RCKI in mass and wingspan. Based on data from the banding station, mass averages for the two species are 6.4 grams for GCKI and 6.8 grams for RCKI (28.3 grams equals an ounce). However, Ruby-crowned Kinglets have significantly longer legs and bills than Golden-crowned Kinglets, and these larger unfeathered surfaces would pose a disadvantage in frigid temperatures.

Despite occasional setbacks due to severe winters, populations of Carolina Wrens have been slowly increasing in Michigan over the last several decades. Currently, the species breeds widely across the southern three tiers of counties in the Lower Peninsula. Records in the Upper Peninsula remain unusual, but reports are becoming increasingly frequent. In the Muskegon area, though still uncommon, Carolina Wrens have been encountered in numerous residential or wooded settings. At MLNP, I banded my first one in 2007. This fall, there has been a pair consistently vocalizing around the banding station. Their readiness to sing outside the breeding season creates a pleasant constrast to the quietude of late fall. Yesterday, I caught one of them in the nets, but the intermediate measurements and the lack of plumage dimorphism among wrens prevents me from determining whether this is the male or female.

Brian Johnson