all the characteristic birds were singing at sunset and after dark a few whip-poor-wills were heard in the distance. I saw a single Nyctarcha gardini; was the first observed on the river. At dusk I distinctly saw swallows flying to roost in the thick alder and the river bank, but was unable to determine the species, though I took them to be H. brevirostris. After dark the large moon shed a dim light over the fen and the nocturnal sights & sounds succeeded the diurnal. Bats were busy somewhere and their shrill squealing was heard every now and then also a cry new to us both; It proceeded from some uncertain bird or mammal or insect that passed over our heads, and was a monosyllabic note very loud & sharp. The cuckoos at one time became very noisy singing many times in succession & answering one another from the opposite bank. Rana pipiens was heard at intervals & close on one place I tried very hard to capture a solitary [Probably Bufo fowleri W.A. 1709] (Crane foot (?)) that was piping his last plaint notes. Reached the landing by 10 P.M. well paid for my trip. I forgot to enter a god. Frogs keep that I saw distinctly from the cars at Waltham.