EASTERN FIELD SPARROW 1223 



in Canada thistle, elderberry, catnip, wild rose, wild lettuce, wild 

 spirea, box elder, lespedeza, lilac, and dewberry. 



The early nests were made largely of coarse dead grass stems and 

 leaves interwoven with finer grasses and lined with rootlets and hair. 

 Some were Imed enthely with black horsehau-, some with very line 

 grass, others with rootlets or a combination of these materials. Later 

 nests usually contained some live grasses. Measurements of 90 nests 

 were: outside diameter 85 to 210 mUhmeters, average 124.3 miUi- 

 meters; outside depth 47 to 110 millimeters, average 63.8 millimeters; 

 inside diameter 43 to 55 milluneters, average 50.2 milluneters; and 

 inside depth 25 to 62 milluneters, average 39.3 millimeters. 



After examining a number of locations, the female chooses a site 

 and starts building the nest. She does all the work on it, but the male 

 is almost always close by, especially at first nests. Before she starts 

 building, I have seen the male occasionally pick up bits of nesting 

 material and offer them to her, but he always dropped them in a few 

 seconds. He usually flies back and forth with her on her trips for 

 material. At later nests he is often busy tending the young of a prior 

 brood, and the female builds anew ^^-ithout his company. He stays 

 m the vicinity, however, and warns her of approaching danger — 

 mammals, hawks, cowbirds — by chipping in alarm. Both birds seem 

 acutely aA\are of cowbirds, and when one appears nest building ceases 

 and the birds start innocently feeding. 



Most of the work is done between 6:00 and 11:00 a.m., and periods 

 of construction are interrupted by periods of rest. The female will 

 suddenly start working, build for several minutes, then stop just as 

 suddenly and begin feeding. She may gather some material within 

 a few feet of the nest, but usually gets it from 20 to 65 yards away. 

 She may spend considerable time selecting and gathering it, but then 

 flies directly to the nest, often landing momentarily a few meters 

 away before flying into it. The coarser material for the exterior she 

 usually brings a piece or two at a time, drops it at the site, and goes 

 back for more. As the nest takes shape she brings finer and finer 

 materials, until by the time she is working on the lining, she often 

 brings it in large beakfids. When interrupted by a cowbird or other 

 intruder, she drops the entire mass, and begins anew later on. 



First nests may take 3 to 7 days, usually 4 or 5 days to buUd. Later 

 nests are generally built in 2 or 3 days, with some lining material 

 occasionally added the 4th morning. Almost invariably after a nest 

 loss, the female lays the first egg in the new nest on the 5th morning. 



Eggs. — The field sparrow usually lays from three to five and rarely 

 SLX eggs. They are ovate and sliglitly glossy. The ground is creamy, 

 very pale greenish or bluish white, and speckled, spotted, or occasion- 

 ally blotched with "army brow^n," "Verona brown," "sayal brown," 



