I spend a lot of time in the woods these days, partly seeking solace but mostly to enjoy nature and photography. And participating in the ongoing Connecticut Breeding Bird Atlas project. Out of curiosity, after surveying at least 10 territorial male Hermit Thrushes (Catharus guttatus) along a 1.4 mile route within the Whittemore Sanctuary Preserve in Woodbury (which is in two of my Atlas blocks), I looked through the preliminary lists for about 100 Atlas study blocks in northwest Connecticut for HETH reports. I came up with only four confirmed breeding and fewer than 20 probables.
Adult Male Hermit Thrush
In Review of the Birds of Connecticut (Merriam, 1877), HETH were described as “Common in migration from mid-April to early May.” By the time of publication of The Birds of Connecticut (Sage, et al, 1943), HETH were “breeding regularly in the northwest part of the state.” The 1982-1986 field work for the first Connecticut Breeding Bird Atlas found Hermit Thrush breeding evidence in 30% of the 600 study blocks, but only confirmed nesting in 36 blocks, most of which were in the northwest and northeast corners of the state.
According to Cornell’s Birds of The World (BOW) the Hermit Thrush is “one of the most widely distributed forest-nesting migratory birds in North America and the only forest thrush whose population has increased or remained stable over the past 20 years.” Hermit Thrush breeding habitat overlaps some with Wood Thrush and Veery here in Connecticut and according to BOW, those species may limit HETH nesting by “interspecific tension.”
Veery (Catharus fuscescens)
Whittemore Sanctuary encompasses almost 700 acres of mixed forest, large enough to create interior forest habitat that many bird species (including HETH) prefer or require. At one location, where I found three singing males all audible from one spot, the habitat was as described in BOW: small openings in a large forest area with fern thicket and grasses (in this case where selective forest management 25 or so years ago created canopy openings), at higher elevations related to surrounding area (in this case 860’ ASL).
One study from Ontario calculated an average HETH territory size of almost 2 acres, about the size of a soccer field or one half of a Costco store. Although males will attack other males trespassing on established territories, HETH “may have a tendency to choose territories near those of conspecifics.” (BOW) The distribution of 10 apparent territories on my 1.4 mile route in Whittemore looks like an example of this tendency. This route traverses the highest elevations in this forest and I have not located HETH during nesting season anywhere else on the 700 acre site.
Locations of Territorial Male Hermit Thrushes along 1.4 mile route
Likely Nesting Habitat
Nests of the subspecies that breeds in the Northeast (C.g. faxoni) are most commonly on the ground, underneath an overhanging tree or shrub branch, or underneath fern fronds or grass clumps (BOW). Prime nesting habitat includes small openings in a large forest area with fern thicket and grasses at higher elevations relative to surrounding area. Nests are apparently very difficult to find (I can attest), so observing nest building, food or fecal sac carrying, or adults attending fledglings are the best bets for breeding confirmation, but even “probable” classifications such as a singing bird present seven days would be valuable information for the Atlas database.
Juvenile Hermit Thrush (early September)
HETH are at the southern edge of their breeding range here in Connecticut and extending along higher elevations of the Appalachians to Virginia, so it seems that the data collected on this species by Atlas work would prove valuable in assessing impacts of climate and habitat change on bird populations and distribution (range expansion and range contraction applies to several species here in Connecticut). I don’t think eBird or the Atlas has requested, but it may be worth noting elevations for any HETH records during the current Atlas research.
Sources:
Dellinger, R., P. B. Wood, P. W. Jones, and T. M. Donovan (2020). Hermit Thrush (Catharus guttatus), version 1.0. In Birds of the World (A. F. Poole, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.herthr.01
The Atlas of Breeding Birds of Connecticut. Louis Bevier, Ed. State Geological and Natural History Survey of Connecticut Bulletin 113.
eBird data from 2014-2018. Estimated for 2018.
Fink, D., T. Auer, A. Johnston, M. Strimas-Mackey, O. Robinson, S. Ligocki, B. Petersen, C. Wood, I. Davies, B. Sullivan, M. Iliff, S. Kelling. 2020. eBird Status and Trends, Data Version: 2018; Released: 2020. Cornell Lab of Ornithology, Ithaca, New York. https://doi.org/10.2173/ebirdst.2018
Sage, J.H., L. Bishop, W. Bliss (1943). The Birds of Connecticut. State of Connecticut Geological and Natural History Survey Bulletin No. 20.
Merriam, C.H. (1877) A Review of the Birds of Connecticut.
all photos © C.S Wood
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