BIRDS OF MARSHALL COUNTY .131 



The following birds were found to be breeding more frequently 

 in the towns and country groves than in the natural nesting 

 sites along the river, (Those marked with an asterisk were 

 not found breeding in the native timber at all) : *mourning 

 dove, flicker, red-headed woodpecker, *kingbird, blue jay, 

 *orchard oriole, *Baltimore oriole, *bronzed grackle, *chipping 

 sparrow, rose-breasted grosbeak, yellow warbler, catbird, brow^n 

 thrasher, western house wren, wood thrush and robin. Others 

 frequenting these groves as freely as they do the native timber 

 include the downy woodpecker, screech owl, goldfinch, cuckoos, 

 and sparrow hawk. 



It is evident that these groves have exerted in the past as 

 they now do, an important influence on the local distribution 

 of breeding bird population. Not even the increase of the Eng- 

 lish sparrow to a commanding position as far as numbers go 

 seems to have anj^ effect in driving other birds from their nest- 

 ing sites. Around some farm yards these sparrow? have filled 

 with their nests every available nook about the buildings, and 

 dozens of their unsightly structures appear in the near-by trees. 

 Yet with them I have found large numbers of robins, mourning 

 doves, chipping sparrows, and other birds nestling apparently 

 undisturbed. 



The only instance of actual destruction of other birds' nests 

 by the English sparrow was one reported by Raymond Jarvis. 

 In this case a robin's nest was entered by a sparrow which 

 dropped out the eggs one at a time. 



The absence of breeding marsh and aquatic birds was very 

 noticeable. Only two small bits of marsh land came to my 

 notice, although a few scattered "kettle holes" probably still 

 exist in the northwestern part of the county. A small cat-tail 

 swamp lying at the base of Mormons Ridge a'Kl an area near the 

 Country Club v.hich was marshy at some seasons furnished prac- 

 tically all of the breeding records for birds of this type, Of all 

 the marsh-nesting species which are common a sihort distance to 

 the north and west, the red-winged blackbird was the only com- 

 mon breeding species here. 



MIGRATION DATA. 

 An area along Iowa river between the Country Club and the 

 ]\Iarshalltown cemetery was chosen for a study of migration and 

 as nearly as possible this area was covered each day. For two 



