494 BULLETIN 17 9, UNITED STATES NATIONAL MUSEUM 



ing to see more of the birds' activities, he turned the box so these 

 occupied rooms could be seen from his own house, but the martins 

 promptly deserted their already occupied nests and rebuilt in rooms 

 on the far side ! 



There are, throughout the country, several particularly noteworthy 

 colonies of martins, but one of the best known, as well as a very 

 populous one, is established in Greencastle, Pa. It is hardly correct 

 to say "one," however, for the martin population is spread here 

 and there over town, in many boxes, but, to the citizens, who take 

 great interest and pride in the birds, it is the Greencastle Martin 

 Colony ! Those who have never seen it have something in store for 

 them. The outstanding attraction of this colony is the tameness of 

 the birds and the intense interest of the citizens in their welfare. The 

 houses are by no means elaborate, simply plain wooden boxes as a 

 rule, with many compartments. They are at low elevations, about 

 8 or 9 feet, attached to telephone poles around the square in the 

 heart of the business district, as well as on hotels and stores. The 

 birds seem to prefer the rush and bustle of the retail district rather 

 than the quieter residential sections. 



These Greencastle martins go back into history. There are records 

 to show that they have been there at least since 1840. One curious 

 lapse occurred in this long tenure, 10 or 15 years after the Civil 

 War. The martins did not return to Greencastle for nearly 15 years ! 

 It was a mystery that has never been completely explained, but 

 G. F. Ziegler (1923), whose article on these birds should be read by 

 everyone interested, considers that the hiatus occurred at the time 

 the English sparrow was most rapidly multiplying and that these 

 two events are connected. Now, however, the martins are again, and 

 have long been, the town's great attraction. The first arrivals appear 

 about the middle of March, and by the second week in April most 

 of the boxes are occupied. 



Eggs. — [Author's note : The purple martin lays from 3 to 8 eggs, 

 usually 4 or 5; the larger numbers are rare. The eggs vary from 

 ovate to elliptical-ovate. They are pure, dead white and practically 

 without gloss. The measurements of 50 eggs average 24.5 by 17.5 

 millimeters ; the eggs showing the four extremes measure 26.4 by 16.3, 

 25.4 by 20.3, 22.7 by 16.0, and 24.9 by 15.8.] 



Young. — The period of incubation has been recorded by various 

 observers as 12, 13, 15, or even 20 days; probably the normal period is 

 12 or 13 days. Incubation apparently is performed by the female 

 only, but both parents assist in the feeding and care of the young. 

 Under favorable circumstances two broods are raised in a season; 

 Audubon (1840) says that sometimes three broods are raised in a 

 season in Louisiana. 



