154



Dr. A. G. Butlkr,



bird being hatched on the morning of the fifteenth day :

unfortunately Mr. Farrar omitted to tell us about his Dliyal-

bird. In the case of the American Blue-bird ( Sicilia sialis ) I

noted thirteen days as the period of incubation, and Dr. Russ

confirms this.


Dr. Russ says that the eggs of the Mocking-bird ( Mimus

polyglot tits') take from thirteen to fourteen days to hatch ; but Mr.

Farrar “ at a rough guess ” says eleven days, which is hurrying

up matters in a most unnatural manner 45 ; guessing in matters

which demand precision is always dangerous: he gives a similar

period to the Cat-bird.


Eggs of the Bearded Reedling, placed under a Canary by

Mr. J. R. Bonhote, hatched in thirteen days ; according to Russ,

the eggs of Liothrix luteus hatch in twelve days, but Mr.

Phillipps found that those of Mesia argentauris took thirteen,

the young appearing early on the fourteenth day.


The White-eared or Persian Bulbul ( Pycnonotus leucotis)

broods its eggs eleven days according to Herr August Wiener.

The Red-vented Bulbul was bred in the London Zoological

Gardens in 1890, and in those of Berlin the year following, but

as Dr. Russ does not state how long the eggs took to hatch, I

conclude that this point was overlooked in both instances. The

Chinese Bulbul (P. sinensis) went to nest in Dr. Russ’ bird-room

in 1893 ; but both nest and eggs were destroyed by a Scaly Dove

squatting down on them.


Dr. Gunther’s observation on the Red-backed Shrike

indicates the period of incubation as fifteen days ; and that

of Mr. St. Quintin on the Waxwing gives fourteen days for that

species.


The Scarlet Tanager bred by Princess Croy in Belgium

incubated for thirteen days; yet oddly enough Dr. Russ states

that Tanagers take twelve days to sit. Frau von Proscheck of

Vienna had a pair of Violet Tanagers which built a nest, but

without result; so that Dr. Russ could hardly have been

influenced by that.


* Incubation may be extended, but hardly shortened by two to three days, excepting

perhaps in unusually warm weather. One of my Canaries laid a double-yolked egg which

took seventeen (instead of thirteen) days to hatch.



