by Carl Strang
How do we “know” what we “know?” It occurred to me back in the 1980’s that much of what I “knew” about most species of animals and plants was information I had gained from reading or from talking with others. I made the decision to assemble a dossier for each animal species, based entirely on my own experience. This was humbling, as the resulting files were small even for common species. From then on I made a point of adding notes as I focused on accumulating more such experience. In recent years my attention has been focused more on singing insects, and so I have added fewer notes to the vertebrate dossiers, but such as I have I continue to share here from time to time in the winter. Today’s focus species, the Nashville warbler, is one we see in the Chicago area only during migration, so at least I have a ready excuse for its small dossier. The odd prefixes for each entry are my date codes.
Observed as a migrant in Lafayette, IN, and at Willowbrook Forest Preserve, DuPage County. Song close to Tennessee warbler’s. First part of song identical, with loud “se-bit’, se-bit’, se-bit’” then instead of emphatic “tee’s” has fewer, slurred, robin-like notes (usually 3). The Willowbrook birds hung around the taller thick shrubs at the edge of the riparian strip.
1MY87. At Willowbrook, a Nashville warbler hopped along and between twigs, 8-15 feet up in riparian woodland. At times very frenetic impression, jerking head around to look in all directions and not pausing long. At other times paused for several seconds and looked all around. Caught 2 small caterpillars within 3 minutes, both by reaching into expanding leaf tufts in box elders. Killed with pecks before swallowing. Not observed to hover-glean or sally.
4MY87. Abundant. In addition to song, a “bick” call, loud and sharp. Another one observed feeding in same way as the one above: much looking between short frenetic hops, and stretching to reach prey from leaf-clusters. Feeding in box elder.
5MY87. Has a chunky body and shows fluttering-hopping advances like a kinglet.
2MY88. First of year singing. Also 7MY at Fulton County Museum property.
19MY88. Female seen at Willowbrook.
31AU88. One observed in Willowbrook riparian area, feeding among low shrubs. Acrobatic, and an aerial pursuit. Reached a lot, too.
29AP89. Heard singing at Von Oven Scout Camp, Naperville.
8MY89. Last noted of spring.
29AP99. First of season noted at Willowbrook. Last noted 14MY there that spring.
3MY99. At Willowbrook, foraging 20 feet up in a box elder. Deliberate, making 1-2-inch hops with much looking around and reaching but no acrobatics. No long jumps, except when moving from tree to tree. Sang infrequently. Slow motion not conspicuous.
2SE99. First migrant of fall noted at Willowbrook. Last seen there 17SE.
1MY00. First migrant heard at Willowbrook.
24SE00. A couple in the Sparrow Hedge, Fermilab.
13OC00. A single, clearly marked adult among Tennessee warblers feeding in tall goldenrods, etc., at McKee Marsh.
14SE02. A single individual at Elsen’s Hill (there were mixed flocks elsewhere) systematically moving from one tall goldenrod to another along a wooded trail edge, perching in or adjacent to the flower heads and searching them closely.
8MY11. Elsen’s Hill. One foraging among the twig tips of a small rosaceous tree in which leaves were expanding. It cranked and twisted its neck so as to peer into and all around the tips while remaining perched in place.