MISSISSIPPI SONG SPARROW 1515 



Pair Formation. — In pair formation, the territorial male gives the 

 same initial reaction to all intruders of his species, that is, he flies 

 at them. Migrating song sparrows respond by leaving; a male in 

 breeding condition puffs out his feathers, sings, and waves a wing, 

 while a female seeking a mate stands her ground and gives special 

 notes and postures. The male "pounces" upon his mate, sometimes 

 colliding with her, sometimes only swooping over her, then flies 

 away with a loud song; she stands still and either gives her copulation 

 note or a threat note. Copulation, however, never occurs in con- 

 nection with pouncing. The male stops singing as soon as joined 

 by a mate. 



The pair normally stays together throughout one nesting season. 

 Yet a female may sometimes follow her young into a neighbor's 

 territory and if he is unmated she may remain with him for the next 

 brood. Remating of pairs a second year has been known in only 8 

 out of 30 possible cases, probably due to the many chances a male has 

 of getting a mate before the return of his last year's mate. A female 

 finding her former mate already mated to another female does not 

 drive off the new female, as does the brown thrasher (Thomas, 1952), 

 but joins another male. There were 4 cases of bigamy, apparently 

 arising when an incubating female lost her mate and attached herself 

 to a neighboring male. 



Nesting. — Typically the nest is built entirely by the female. An 

 exceptional male, while unmated, built 2 incomplete and one complete 

 nest; later he helped his mates built 3 nests (Schantz, 1937). The 

 nest is a rather simple affair built largely of dead grass and weeds, 

 with a few fine roots and pieces of grape-vine bark, and lined with fine 

 grass and occasionally horse hair. Renesting regularly occurs if a 

 nest fails, until the nesting season is at its end. The song sparrow 

 shows its adaptability in the nest sites chosen. The requisites are 

 secure support and concealment. In April almost the only situations 

 on Interpont offering these characteristics are on the ground; here 

 under tufts of grass, weed stalks or thistles, and often in a natural 

 depression, nine-tenths of the nests of the first attempt have been 

 situated. One-third of the nests of the second attempt were placed 

 above the ground, as were two-thirds of the third attempt. Few nests 

 were built more than 3 feet above the ground. Replacement nests 

 were built at 10 to 55 yards from the nests replaced, averaging 25 

 yards. 



Reginald F. James wrote Mr. Bent from Willowdale, Ontario: 

 "The Song Sparrow begins to nest around April 20th, and its first nest 

 is usually placed on the ground. The second nest is built about 18 

 inches above the ground level. If and when a third nest is con- 



