Olive-sided FlycatcherContopus borealis (Swainson)
Status Fairly common in summer. Breeds. Usually arrives in the second half of May (average 20 May, earliest 5 May); birds on Sable Island on 25 April 1975 and in Shelburne County on 30 April 1973 were very early. Numbers during breeding season have decreased markedly in the past 50 years for no known reason. Before 1940 it was customary to find pairs occupying groves of mixed deciduous and coniferous trees in settled areas and forested regions. Migration is well underway again during mid-August, with peak movements towards the end of the month. Last sightings are normally in September, with stragglers much later (average 16 September, latest 8 November).
Description Length: 18.5-20.5 cm. Adults: Dark olive above, darker on wings and tail; no wing bars; white throat and broad white stripe down centre of breast and belly; rest of underparts dark olive; tufts of fluffy white feathers sometimes show on upper flanks, but often are concealed by closed wings.
Breeding Nest: Made of twigs, and weed or grass stems, lined with rootlets or beard lichen, the choice of lining obviously based on availability. Most nests are strong and compact, but a minority are loosely built and sometimes barely adequate. Of 43 nests examined, all but one were saddled on horizontal branches 2-15 m off the ground; the exception was in a hemlock, about 6 m up, placed close to the trunk and well concealed by thick-growing sprouts. This last tree was in an open sunny glade, with insects readily available, but without a preferred type of nesting tree in the immediate vicinity, which probably explains the deviation. All other nests were exposed. The trees selected by the 43 flycatcher pairs were: spruce, 24; apple, 8; fir, 6; elm, 3; locust, 1; and hemlock, 1.
Eggs: 2-4, usually 3; creamy white, spotted (sometimes beautifully wreathed) chiefly around the larger end, with various shades and densities of lavender and chocolate. Of the 43 nests, 32 held three eggs; 8 held four; and 3 contained two. Laying was completed in all, the sets of two being second attempts. Nesting begins early in June, two sets of three fresh eggs having been examined on 11 June 1914. If the first nest is destroyed, the pair will try again, but I have no evidence that a third nest is ever attempted.
Range Breeds from central Alaska to Newfoundland and southward; in the east, to the mountainous regions of North Carolina. Winters in South America as far south as Peru.
Remarks On his return in spring, the male selects a territory for nesting and all rivals are immediately challenged. Sitting on the topmost dead branch or the highest tree in his little kingdom, with an unobstructed view in all directions, he remains alert and upright, like a sentinel on duty, for hours at a time. During the nesting period the male is practically never absent from his chosen domain. His clear, whistled call, which permits several equally euphonic translations, can be heard far off as he orders his listener with come right-here or quick more-beer. There is the story of a trapper in the back country who, finding his bear trap empty, claimed he was taunted by a very impudent bird perched overhead that kept jeering at him with what no-bear. The first word is shorter and weaker than the other two where emphasis is placed, and the final note is usually drawn out and slurred downward.
When the safety of the nest is menaced, both birds will join in an attack upon the intruder. I once saw a red squirrel knocked off a nest limb by one of two irate parents; so intense was their combined fury that the squirrel chose to escape further punishment, scurrying away across the ground with both birds in hot pursuit. The presence of young in this particular nest probably increased the parents' aggressiveness. Their note at such times is a low-pitched, angry tip-tip-tip, uttered rapidly and repeated incessantly while danger threatens.
Questions? Comments? E-mail us at: Museumfirstname.lastname@example.org
Credits and copyright information. Last updated February 20, 1998
Best viewed with Netscape 3.0 or Internet Explorer 3.0 or later.
For further information contact Webmaster, Nova Scotia Museum.