Jail., i‘ni 
A HISTORY OF CliRTAIX ('.RITVT lloRXFI) OWLS 
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began to visit the nest as often as possible to ascertain as nearly as I could when 
the chicks appeared and how long the hatching process lasted. It was not until 
March 6, at 2 p. ni., that I found one of the eggs pipped-, a small round area no 
larger than a pea being broken. On March 7 at the same hour the broken area 
was the size of a dime. I could distinctl}" hear, however, several times repeated, 
the low twittered note of the still imprisoned chick. The other eggs still .showed 
no sign, bad weather and pressure of other work now prevented a further visit 
until March 11, at two-thirty o’clock. Two verj' callow owlets were now in the 
nest and one slightly pipped egg. The young birds were not completely protected 
by their white down as yet, the bare skin being visible between the tracts. On 
March 16 three young owls of different sizes were found in the nest, one being 
quite markedly smaller than the other two. The query remains: how long does it 
Ibg. 11. APRIL 22 , 1007; DORS.-VL ANU) LATKRAL VIRWS; AGK KORTV-ONp; TO F()KTV-in\’H D.WS 
take a Great Horned Owl’s egg to hatch? The above are the data kejit and any- 
one can make estimates on them. It seems certain that these birds did not lay an 
egg oftener than once in two davs and that the period of inculcation could not have 
been less than thirty days, with the probabilities on the side of a rather longer period. 
For our second year’s work we had the experience of the first to go on, we 
were more confident of the owlets’ ability to bear ex]cosure, and so decided to 
photograph them at least once a week, let the weather offer what it would. And 
the offerings were of sufficient variety! On March 16, with the young from four 
to eight days old approximately, the temperature was well above freezing and 
comfortable, but we were unable to expose a plate until 4 p. m., the sun became 
covered with black clouds, and we were on the shady side of the tree. We were 
not hopeful, but a long exposure accomplished our purpose. In addition to the 
parts of three adult cotton-tails and one Bob-white which the camera shows, a 
