THE breeding area of the Connecticut Warbler, Oporornis agilis, ex-
tends from the Peace River area of British Columbia (Cowan, 1939)
eastward through Alberta (R. C. Harlow in Bent, 1953; Soper, 1949;
Godfrey, 1952), Saskatchewan' (Godfrey, 1950), Manitoba (Seton,
1884; Macoun and Macoun, 1909; Cartwright, 1931; Short and Waller,
1937; Godfrey, 1953), Ontario (Magee, 1923; Baillie and Harrinon,
1937; Baillie, 1950; Todd, 1943; Smith, 1957; Brown, 1947) to Quebec
(A.O.U. Check-list, 1957; Smith, 1957). The southward limits ap-
parently are in northern Minnesota (Huff, 1929; Kilgore and Brecken-
ridge, 1929), northern Wisconsin (Gromme, 1942), and northern
Michigan. A considerable number of observations have been accumu-
lated during more recent years in northern Michigan. Because these
have been made at the southern limit of the breeding range, they are
of importance to our knowledge of the distribution as well as the gen-
eral biology of the species.
IC[IIGAN RECORDS
There have been many misidentified birds recorded as Colmeet]cut
Warblers in the Michigan literature. We will attempt here to make the
necessary corrections.
1. O. B. Warren (1895: 192) reported a nest of the Connecticut Warbler in
Marquette County in August 1894 but later (1898: 193) xvrote that it was a
mistake and that these birds were Yellowthroats (Gcothlypis trichas).
2. N. A. Wood (1905: 178), and Wood, Peet, and McCreary (1906: 119)
claimed that a female and young were taken in the Porcupine Mountains,
Ontonagon County, in the summer of 1904. Wing (1940: 191) and Wood (1951:
414) corrected this when they found the birds were Mourning Warblers (Oporornis
philadelphia).
3. E. A. Arnold (Kilgore, 1930:24, 26) is said to have collected a set of two
eggs of the Connecticut Warbler 27 May 1899 in Calhoun County. Since we
have lived nearly all of our lives in and adjacent to Calhoun County, and we and
no one else has ever seen the species there in summer, we feel this record is not
valid. Mourning Warblers occasionally will remain this far south in Michigan,
but we know of no logical Connecticut Warbler habitat in this or any nearby
county.
4. J. Claire Wood (1905: 130) has recorded a sight observation of this species
near Detroit, 3 July 1905, but this has already been discounted by Zimnmrman
(1955: 15), and we agree with Zionmerman.
5. Josselyn Van Tyne (1923: 25) observed a pair on 19 July 1919 at Mismer
Bay, Les Cheneaux Islands, Mackinac County. The female had food in her bill
and scolded as though young were nearby. He also saw a female bird near
Hessel, Mackinac County, on 9 August 1919. These appear to be the first
authentic smnmer records.
6. Cheboygan County, Burt Lake. Fortner and Metcalf (1929: 250) observed
two Connecticut Warblers on 12 July 1921 in a cedar bog but gave no details.
The birds were not collected.
7. Chippewa County, Munuscong State Park. On 10, June 1934 Walkinshaw
collected a singing male and observed another on 14 June 1934.
8. Luce County, McMillan. Bryens (1941: 48) observed a Connecticut War-
bler south of here on 23 July 1922. The area in which he lived was not typical
breeding habitat, so the bird must have been a wanderer. In the great Tahquame-
non Swamp, Walkinshaw (1936: 220) found two singing males on 9 June 1935
and observed these birds 10, 11, 12, and 18 June 1935. We returned to the area
in 1948 and observed two singing males daily from 23 June until 3 July. We
observed another singing male here on 2 July 1958.
9. Alger County, five kilometers (three miles) east of Shingleton. On 1 July
1941 G. A. Ammann (1944: 48) observed a singing male.
10. Chippewa County, Trout Lake. On 29 May 1948 Ammann (Wallace and
Black, 1948: 173) found seven, possibly eight, singing male Connecticut Warblers.
11. Schoolcraft County, Seney, five kilometers (three miles) east. We found
a singing male here on 26-28 June 1952.
12. Ontonagon County, seven kilometers (four and a half miles) north of
Ewen. Arthur Peters (notes to University of Michigan Museum of Zoology)
found several singing males in the summer of 1954. On 21 June 1956 Dyer with
Dr. and Mrs. W. Powell Cottrille observed several singing males. On 13, 17,
and 18 June 1957 the Cottrilles, Mr. and Mrs. Arthur Peters, and we found
eight singing male Connecticut Warblers, and on 1 July 1960 we found the first
Michigan nest. On 2 July 1960 Eliot Porter, Betty Cottrille, and we found a
young bird out of a nest some little distance north of the nest that we found the
previous day. One specimen was taken.
13. Marquette County, 20 kilometers (12 miles) east of Marquette. We found a
singing male on 13 June 1957 in a jack pine, semi-open area.
14. Oscoda County, Red Oak (T28N,R1E, section 26). D. Zimmerman (1955:
12-19) found a singing male Connecticut Warbler on 30 June 1954 and collected
another 9 July 1954. D. Middleton, A. J. Berger, and W. P. Nickell (Kenaga,
1960: 37) found a Connecticut Warbler in Oscoda County 18-24 June 1959.
MIGRATION AND BEGINNING NESTING
The Connecticut Warbler is a late-spring migrant, usually arriving
in southern Michigan late in May. Some birds are observed even into
the first few days in June. At Battle Creek, Calhoun County, Walkin-
shaw has observed singing males on 23 and 27 May 1930, 22 and 23
May 1931, 26 and 27 May 1937, 22, 24, and 26 May 1938, 30 May
1945, 21 May 1946, 4 June 1954 and in Lee Township, Calhoun County,
18 May 1957; in Muskegon County, 29 May 1954 and 31 May 1958.
With William Freeman, we observed a singing male near Cross Village,
Emmet County on 29 May 1960.
Spring University of Michigan Museum of Zoology specimens indi-
cate a similar trend in migration:
Berrien County (Birchwood Beach) by N. A. Wood 27 May (3 females), 29
May (1 female), 30 May (1 female) 1918.
Kalamazoo County (Kalamazoo) by F. H. Chapin 23 May 1880 (1 male), 28
May 1883 (1 male). (Gull Lake) by C. J. Henry 19 May 1933 (1 male).
Washtenaw County (Ann Arbor) by N. A. Wood 18 May 1911 (1 male); 25
May 1913 (1 male); by A.D. Tinker 3 June 1928 (1 male).
Wayne County (Grosse Ile) by B. H. Swales 5 June 1907 (1 male, 1 female);
(Detroit) by D. Middleton 22 May 1950 (1 male).
Iosco County (Hale) by C. Oxvens 31 May 1954 (I female).
From the date of the nest that we found in Ontonagon County,
Michigan, on 1 July, with young already leaving the nest and young
out of another nest the following day, it would appear that egg laying
would have begun by 5 June and nest building in late May or early
June.
Probably many of the migrating males of late spring in Michigan are
going farther north into Canada to breed.
During the spring migration the male Connecticut Warbler often
sings rather regularly in the early morning, and it is because of this
that we have been able to locate the birds. Often they go along a brush-
grown roadside moving northward and singing as they go but usually
near the gronnd.
SONG AND SCOLDING NOTES
Much has been written about the Connecticut Warbler's song. It
is very loud and penetrating. We feel that it is even louder than the
songs of Water-thrushes and the Kirtland Warbler (Dendroica kirt-
landii). Seton (1884) described the song as beecher-beecher-beecher-
beeher-beecher-beecher and later as Fru-chapple fru-chapple fru-
chappie whoit.
One description by us has been freecherty-freecherty-/reecherty-
freech. Again it resembled I/ir9inia-vir9inia-zr#inia and again a
shorter song resembling the song of the Yellowthroat I4/eechery-
weech. At McMillan in 1948 we watched two males every morning for
some time. Usually they began singing very early in the morning, but
on 24 June the first male sang at 0520 and the next morning it was
even later, at 0618. On 1 July one male began singing at 0521 while
on 3 July one male was singing when we arrived at 0530 and con-
tinued to sing until 0607. In 1935 two males were timed at 0500, sing-
ing at the rate of six times per minute. V% found that males preferred
[ .Auk
382 WALKINSHAV ^r' D3/4}m, Connecticut Warbler [Vol. 78
to sing about six-eight meters from the ground in a taller, dense tree
and often did not move from that spot for a long period of time.
They were even hard to flush at times from their singing perch.
Powell Cottrille shook a tree at Ewen in June 1956 vhile the bird
was singing, and it continued to sing regardless.
The scolding note is unique and different than any scolding note we
have heard, a sharp plink, higher pitched than the call of the Mourning
Warbler. Both birds gave this call, and because they were so vociferous
we knew where they were nearly all of the time until they ran (not
hopped) around close to our feet.
The population of Connecticut Warblers in Michigan has never been
sufficiently dense for the development of conspicuous territorial defense.
The male that we found at Ewen was singing at least 145 meters from
the nest and about 235 meters from the next nearest male Connecticut
Warbler. We watched him for some time, when suddenly he flew
to the opposite side of the tree, captured an insect, and flew north-
ward between two evergreen trees. When we reached the approximate
location, both the pair of Connecticut Warblers and a pair of Mourning
Warblers scolded us. Neither paid much attention to the other.
Nsrxc
The above Connecticut Warblers were very vociferous and came
regularly with food for the five young. They landed near the nest site,
then walked beneath the vegetation for the last 9-15 meters, so that it
required some time actually to locate the nest.
The vegetation above and within a meter of it included: Bracken fern (Pterls
aquilina), a very small basswood (Tilia americana), some strawberry (Fragarla
sp. ?), a violet (Fiola sp,?), morning glory (Ipomoea sp.?), goldenrod (Solidago
sp.?), fireweed (Epilobium angustifolium), and large-leafed aster (Aster sp.?).
In the vicinity were white pine (Pimts Strobus), white spruce (Picea canaden-
sis), black spruce (Picea mariam), balsam (Abies balsamca), cat-tail (Typha lati-
Jolla), large blue flag (Iris versicolor), some xvilloxvs (Salix sp.?), scattered
quaking aspens (Populus trcmaloides), marsh marigold (Caltha palustrls), gold-
thread (Coptis tri[olia), meadoxvsweet spirea (3'plrca salicifolia), shadbush (Ame-
lanchier canadetsis), golden avens (Geum stricture), red raspberry (Rubus idaeus),
thimbleberry (Rubus sp.?). some clover (Trifolium sp.?), sugar maple (Acer
saccharum), red maple (Acer rttbrttm), red-osier dogwood (Cornus stolonifera),
black ash (Fraxinus ,igra). dogbane, self-heal (Prunella vulgaris), ironveed
(Feronia altissima). yarrow (Achillea sp.?), and hawkweed (Hieracium aurantia-
The trees vere widely scattered, with many openings between, pro-
ducing a rather parklike area. The water plants grew along the side
of a very small stream. In the majority of clearings, grass, some
I Auk
384 WALKINSHAW AND DYER, Connccticu! l/Farbler tVol. 78
timothy, and, in places, some sedges grew. The ground cover was ex-
tremely dense.
The nest rested on dry ground. It was very bulky and when
collected and dry weighed 19.8 grams. The outside dimensions were
120 x 142 mm. across and 55 mm. deep. Inside it measured 59 mm.
across and 52 min. deep. It was made of a foundation of dead leaves
and other dead debris piled into a mass, then lined with coarse grass with
finer grass on the interior. Like many birds that build nests in both
bog and on dry land, Connecticut Warbler nests vary according to their
location. The one described by Huff (1929) was not bulky, and was
sunken into sphagnum moss. Nashville Warblers (Vermivora ruff-
capilla) and Palm Warblers (Dendroica palmarum) both nest similarily
to the Connecticut Warbler--on dry land and in bogs in the sphagnum
moss. The Palm Warbler, however, usually builds its nest on top of
the moss; the Nashville Warbler in the moss on the side of a hum-
mock. The nest of the Connecticut Warbler is more like the nest of
the Palm Warbler than like that of the Nashville.
The juvenal nestling Connecticut Warbler is quite dark on the back,
a dark brown with no evidence of any lighter markings at all. There
is no eye ring. The sides beneath are lighter brown, becoming yellow
below. The throat is buffy. The tomia are yellow; the inside of the
mouth a pinkish-orange. The legs are light-flesh color. Weights of
two of the nestlings ready to leave the nest were 10 grams. Wings of
four measured, 36, 36, 36, and 35 mm.; tails, 6, 6, 7, and 7 min.; tarsi,
20, 21, 22, and 22 mm.; culmen 8.2, 8, 8, and 8 mm. The adults were
caught and measured. The male weighed 13.5 grams. His wing
measured 68 mm.; tail, 54 mm.; tarsus 21 mm.; exposed culmen, 12
min. The female weighed 13.2 grams. Her wing measured 69 mm.;
tail, 51 mm.; tarsus, 20 min.; exposed culmen, 12 min.
The average wing measurement of 15 males in the University of
Michigan Museum of Zoology was 71.5 ram.; 9 females, 66.8 ram., con-
siderably longer than wings of the Mourning Warbler. In addition to
the longer wing the Connecticut Warbler has longer under tail coverts,
and adults always have a distinctive white orbital ring. The male is
olive-green above, gray without any black on the throat, and yellow
below this. The female is browner on the throat but also has the
complete eye ring.
FALL I'[IGRATION IN MICHIGAN
There has been some suggestion of possible differences in migratory
route in the fall from that of spring. Yet a number of specimens exist
from southern Michigan indicating that many birds must follow the
same route as in the spring. The following specimens are in the
University of Michigan Museum of Zoology:
Isle Royale by W. G. Fargo 4 Sept. 1924 (1 juv. female)'.
Chippewa County (Munuscong State Park) by W. G. Fargo 5 Sept. 1927 (1
juv. female).
Saginaw Bay (Charity Island) by N. A. Wood 3 Sept. (1 female), 6 Sept. (1
female), 8 Sept. (1 male), 15 Sept. (1 female) 1910.
Muskegon County (Laketon Twp.) by L. H. VValkinshaw 14 Sept. 1957 (1
male).
Livingston County (Edwin S. George Reserve) by G. M. Sutton, 5 Sept. 1940
(1 juv. female); (Whitmore Lake) by R. E. Stewart 3 Sept. 1938 (1 female).
Jackson County (Portage Lake) by R. E. Stewart, 27 Aug. 1938 (2 females).
Washtenaw County (Ann Arbor) by N. A. Wood, 13 Sept. 1926 (1 male).
(Pittsfield Twp.) by A. J. Berger, 7 Sept. 1955 (1 juv. male).
Wayne County (Palmer Park) by B. H. Swales, 8 Oct. 1905 (1 female); 30
Sept. 1906 (1 female).
SUMMARY
The Connecticut Warbler has been found in summer from the Peace River Parklands eastward to Rupert House, Quebec, southward to Aitkin County, Minnesota, at Wascott, Douglas County, Wisconsin, and now at Ewen, Ontonagon County, Michigan, and at times even into the Lower Peninsula, at Red Oak, Oscoda County, Michigan. A nest was found in northern Michigan on the ground in an aspen, balsam parkland. It contained five young, all ready to leave the nest on 1 July 1960. They left during the day.
Young birds (probably about 9 or 10 days old) are an olive-brown on the back, without any wing bars and no eye ring. Below, on the sides, they are a lighter brown, the same on the throat, gradually blending to yellow on the lower parts. The tomia are yellow; the inside of the mouth, pinkish-orange. The legs are light-flesh color.
Food of the young consisted of moths, green larvae, and other insects brought by both parents. Excreta were usually carried away from the nest at this time.
The juvenal Connecticut Warblers weighed 10 grams. Their wings measured 35-36 mm. Adults weighed 13.2 and 13.5 grams. The average wing measurement of 15 males in the University of Michigan Museum of Zoology was 71.5 (69-74) mm.; of 9 females, 66.8 (64-70.5) mm.
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819 North .4re., Battle Creek, Michiga,, and 402 John St., Union
City, Michigan.