PRAIRIE MARSH WREN 253 



are generally ovate, sometimes more rounded and rarely more 

 pointed ; they are not glossy unless heavily incubated. Marsh wrens' 

 eggs are unique in color, the general effect being dull brownish, 

 "Verona brown" to "snuff brown," or the color of dry, powdered 

 baking chocolate. The ground color varies from "snuff brown" to 

 pale "pinkish cinnamon" ; it is generally evenly sprinkled with minute 

 dots, or very small spots of darker shades of brown, often partially, 

 or wholly, obscuring the ground color ; these markings are sometimes 

 concentrated into a ring or a cap at the largo end. F. W. Braund 

 tells me that "light or stony gray" eggs are often found in Ohio. I 

 have seen eggs with a pinkish ground color and reddish brown spots 

 that resembled the eggs of the house wren, but these are rare. Very 

 rarely an egg, or a whole set of eggs, is pure white and unmarked. 



The measurements of 40 eggs average 16.5 by 12.4 millimeters; 

 the eggs showing the four extremes measure 17.8 by 12,1, 17.6 by 

 13.3, 15.0 by 13.0, and 17.6 by 11.2 millimeters. 



Young. — The incubation period, as noted by several observers, is 

 about 13 days, and the young remain in the nest for about the same 

 length of time, or a day longer, if not disturbed; Dr. Welter (1935) 

 says 14 days. Incubation seems to be performed wholly by the female, 

 and she feeds the young while they are in the nest; the male assists in 

 this afterward. Following are some of Dr. Welter's observations on 

 the young : 



The type of food delivered to the young by the female is determiued to a 

 certain extent by the age of the nestlings. At first this consists of very small 

 juicy morsels such as mosquitoes and their larvae, larval Tipulids, midges, and 

 other delicate forms. The mother brings a whole beakful of food to the nest 

 at one time and parcels it out to the hungry occupants. * * * During the 

 morning and evening approximately 10 trips are made per hour with food, but 

 during midday this number is somewhat reduced. 



As the nestlings grow the insects brought to the nest become appreciably larger 

 in size. Ground, diving, and long-horned beetles, caterpillars of various assort- 

 ments, sawflies and other hymenoptera, and other accessible forms now consti- 

 tute the diet of the ever-hungry young. Sometimes the insect is so large that 

 the young bird experiences difficulties in swallowing it. In such instances the 

 female takes the hexapod to the side of the nest, chops and tears it into several 

 smaller morsels, and then brings it back for a second trial which is usually a 

 success. * * * 



Even when the nestlings are very young, little time during the day is given 

 to brooding. Usually after a feeding or two the young are brooded for a few 

 minutes and then feeding is resumed. My records show a total brooding of 

 18 minutes per hour when the young are 2 days old. As the nestlings increase 

 in size the brooding periods become shorter and the intervals between such 

 periods become longer, so that, after the first week, they are discontinued during 

 the hours of daylight. * * * 



The excreta, enclosed in their envelopes, are removed by the female after feed- 

 ing. These droppings are usually carried some distance from the nest and 

 deposited, but occasionally the female has been observed eating them. * * * 



