28 Vol. XXI 
EVIDENCE THAT MANY BIRDS REMAIN MATED FOR A 
NUMBER OF YEARS 
By N. K. CARPENTER 
THE Conpor, entitled ‘‘Evidence that many birds remain mated for 
life’’, numerous incidents were recalled by the writer tending to bear 
out Mr. Willard’s conclusions. I have long held the same general idea as was 
advaneed 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. This is shown by the fact that while a certain pair of birds that nest in 
the same 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, 19138 and 1917. It was not visited in 1906 or 1912, but I have lhttle 
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 the 
birds were seen close by each year. The nest and set of eggs were taken, and 
the past spring (1918) the pair moved to a narrow crack about twenty-five feet 
away in the same boulder pile. 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 that 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 of 
- 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 Hummingbira 
(Archilochus alerandri) 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 past 
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 where 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. 
W rue reading an article by Mr. F. C. Willard in a recent number of 
