July, 1910 SOME COLORADO NIGHT HERON NOTES 119 ? Just preceding the return of the birds in 1908, a spark from a passing engine ignited the dry rushes, and the nesting site of the preceding years was entirely obliterated. The birds were first noted on the same date as in 1907--April 26-- but a careful search of all the lakes failed to reveal their nesting place until, on May 16, in an endeavor to discover the nesting place of the many Great Blue Herons which frequented the Bart chain of lakes, we stumbled onto the rookery of both. It was located some ten miles southwest of the lakes in a grove of cottonwood trees on the bank of the South Platte River. The Great Blue Herons had selected the tops of some lofty trees for their nesting sites, and almost beneath them in a dense grove of second-growth cottonwoods were the Night Herons' nests, a hun- dred or more of them, ranging from ten to twenty feet atJove the ground in saplings two to four inches in diameter. They were practically identical in construction with the nests which we had examined two years before in the willow thicket over Fig. 37. THE SAME NEST JUNE 30, 1907; THE NEST COMPLETELY INUNDATED AND THE FOUR GREAT STUPID BIRDS HUDDLED TOGETHER IN THE NEST, DRENCI-IT TO THE SKIN, THE VERY PICTURE OF DEJECTION AND DESPAIR the water, but were, if anything, a trifle larger and better bilt. The parent birds were quite tame and seemed much excited over our intrusion. On this date, May 16, most of the nests contained incomplete sets---one, two and three eggs--altho one set which was collected was heavily incubated. On June 5 many of the nests contained freshly hatcht young and two birds were seen that were almost large enough to fly. On July. 5 nearly all of the young birds were well grown and were out of the nests, climbing awkwardly about among the branches which, being heavily foliated, afforded them good concealment and protection from the broiling sun. A year later, on May 9, 1909, a visit to the heronry found the Great Blue Herons busily nesting, but not a Night Heron was to be seen. A diligent search, however, disclosed a new rookery, some two miles above the old one, excel- lently concealed in a very dense grove 9f young cottonwood saplings near the river bank. The nests, of which there were about a hundred, ?vere identical with those
