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After this extending the banding season later than the previous four falls, I finally closed the Muskegon Lake Nature Preserve station on November 29. The November extension provided a much clearer picture of late season passage, which had been somewhat truncated in the past (I closed November 6 last year). As an example, good numbers of Black-capped Chickadees have moved through the station during the last two years (118 in 2009, 109 in 2010), but the historical totals may not have accurately depicted the passage curve as birds were still arriving at the end of the season. Fortunately, the 2010 results indicated that we probably have not missed many. The migration tapered quickly during the second week of November, and only two new individuals were captured after November 15.
Altogether during the 2010 autumn, we banded 1225 birds of 63 species. American Goldfinch (193), Black-capped Chickadee (109), White-throated Sparrow (100), and American Tree Sparrow (91) were the most plentiful. There were no outstanding rarities, but as in every year, there were interesting visitors (like the aberrantly orange House Finch above). More station details will await the seasonal report.
As in 2009, I spent a lot of time attacking certain invasive plants. Oriental bittersweet is a particularly noxious species, and I pulled or cut all I could find around the banding station. It still remains abundant in other places on the preserve, and in such places, the bird and native plant life seriously suffer.
Many people evaluate the wildlife value of specific plants simply by their fruit or seed production. However, the vegetative contribution toward roosting cover, nesting substrate, climate control, predator avoidance, disturbance reduction, and arthropod habitat makes berry forage seem almost trivial by comparison. Nevertheless, many late season migrants are highly frugivorous. Moreover, not all fruit stocks are created equal. At the preserve, pokeweed and honeysuckle are consumed voraciously (the latter especially by Cedar Waxwing, like the October individual pictured above), while bittersweet and highbush cranberry are barely touched. Black cherry is another favorite, and grape has appeal to larger species. Autumn olive berries are devoured by chipmunks on the bush, and ground-feeding birds consume them after they fall. This year at MLNP, the crop of honeysuckle, grape, and dogwood was poor, whereas highbush cranberry, privet, and viburnum was abundant. If this pattern is prevalent elsewhere in the county, then frugivorous birds may be hard to find on the Christmas Bird Count.
In any case, while checking the station on December 11, I did see two unusually tardy species: Fox Sparrow and Gray Catbird. The catbird is the most common breeding species at the preserve, but habitat deterioration at the site has produced a decline. The last birds generally leave in early October, but in 2009 I did capture one on November 2. One would almost expect such a late bird to be thin or weak. On the contrary, this monster was by far the heaviest catbird that I have ever handled (1.5x the weight of a normal individual). Unlike mammals, which bulk up to survive a winter, birds bulk up to fuel a migration -- this bird apparently did not get the memo.
- Brian Johnson
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