100 



NORTH AMERICAN FAUNA 73 



Yellow-bellied Flycatcher (Empidonax flaviventris) 

 Status: Regular migrant, one nesting record. 



Migration: Uncommon spring migrant in the Western Upland and Central 

 Plain, locally common in the Northern Highland. Fairly common to locally 

 common fall migrant in all regions. Earliest spring migrants arrive 

 10-15 May, reaching the Northern Highland about 20 May. Peak migration 

 occurs 20-30 May and departure from most areas by 5 June. Fall migration 

 begins by mid-August (earliest— 31 July 1967, Washington County). Peak 

 movements occur 15 August to 1 September and birds depart by 15 Sep- 

 tember. 



Nesting Season Distribution: Bernard (1967) cited the only known nesting 

 record for the region, a nest with four eggs near Wascott (Douglas County) 

 on 21 July 1941. Green and Janssen (1975) cited the observation of singing 

 males near Bruno, Pine County. I observed singing males along the St. Croix 

 River near Gordon, Douglas County, on 20 July 1976, and again on 10 June 

 1977. In neither instance were nests observed. The yellow-belHed flycatcher 

 is probably more widespread as a nesting species than available records indi- 

 cate because of the vast amount of suitable nesting habitat in the Northern 

 Highland. 



Habitat: The 1976 and 1977 records were obtained from an extensive stand 

 of black spruce- tamarack swamp adjacent to the St. Croix River. At other 

 seasons, this flycatcher regularly uses a variety of edge situations. 



Acadian Flycatcher {Empidonax virescens) 

 Status: Casual migrant and possible nesting species. 



Records: Observations of this bird at the northern Umit of its range have 

 been sporadic. Because of their occurrence during normal nesting periods, 

 this species must be considered a possible nesting bird. St. Croix County 

 records include 12 May 1974 at Roberts, and 15 May 1973, 21 June to 5 July 

 1963, and 22 July 1965 at Hudson. One record exists of this species in the 

 Minnesota Counties. Bra the (1976) described observations at Franconia, 

 Chisago County, on 8 and 16 June 1976. 



Habitat: A species of deciduous forest habitats including Lowland Decid- 

 uous Forest and heavily wooded hillsides in mesic Southern Deciduous 

 Forest. 



Willow Flycatcher {Empidonax traillii) 



The decision of the American Ornithologists' Union (AOU 1973) to spUt 

 the Traill's flycatcher {Empidonax traillii) into two separate species created 

 many problems in range delineation. Before that time, both willow and alder 

 flycatchers were recorded as one species, even though song and habitat dif- 

 ferences were readily apparent. Fortunately, S. D. Robbins maintained sepa- 

 rate records of both species based on song, and from his work it is possible to 



