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28 Vol. XXI EVIDENCE THAT MANY BIRDS REMAIN MATED FOR A NUMBER OF YEARS By N. K. CARPENTER HILE reading an article.by Mr. F. C. 'Willard in a recent number of THE CONDO?, entitled "Evidence that many birds remain mated for life", numerous incidents were recalled by the writer tending to bear out Mr. Willa'rd's conclusions. I have long held the ame general idea as was advanced in his paper, but believe further that "separation for cause" is not by any means unknown in the bird world. It might also be stated that the instinct to return to the former nesting site is probably equally strong in both male and female. Thls is shown by the fact that while a certain pair of birds that nest in thesame place for several years will have individual characteristics so pronounced that the location of the nest, and type of markings and shape of the eggs, can be told in advance to a certainty, as stated by Mr. Willard, there will suddenly be a change. The same location is still used, but the eggs are entirely different. A new female apparently is in possession, evidently brought there by the male of the former pair. His spouse may have died or grown too old to rear a family, but it was probably a good and sufficient reason. The Dotted Canyon Wren (Catherpes mexicanus punctulatus) is one of our local species that will return to the same niche in a boulder year after year to rear a family. I have under observation one pair that was first located in 1905. The nest was on a shelf about eight inches square in the side of an immense boul- der. This little pot-hole was used to my knowledge in 1905, 1907, 1908, 1909, 1910, 1911, 1913 and 1917. It was not visited in 1906 or 1912, but I have little doubt that the spot was used these years. In 1914 the birds were present, but the nest had been removed, and they had evidently decided on a change of loca- tion. It was not until 1917 that they returned to the old nook, although birds were seen close by each year. The nest and set of eggs were taken, and thc past spring (1.918) the pair moved to a narrow crack about twenty-five feet away in the same boulder ?ile. Judging from the markings of the eggs during this period of years the male changed mates or secured a new one but once. The set always consisted of five eggs excepting upon one occasion when six were laid. April 9 was the earliest date ?hat the clutch was found completed and April 25 the latest. Other pairs of this species that I have found in the last few years always return to the old nest if it is not disturbed, even though the set eggs may have been taken, but the histories of these birds, so far as I know them, are short in comparison with that of the pair just cited. Our hummingbirds also are easily watched. A Black-chinned Hummingbird (Archilochus alexandri) that I know. of, built a nest on an electric wire within six inches of a porch light for four successive years. The current was on every evening, but the light did not seem to disturb the bird, who reared one family each season. Another of the same species has constructed its nest for the pas? four years under an old log bridge, for three successive seasons a new story being added to the old nest. There is a small ravine near here lined with a few stunted sycamores wher? several hummingbirds, both Black-chinned and Costa (Calypte costae) nest each year. In fact, these birds are so consistent in returning to this particular gully that we have named it Hummer Canyon.