FAMILY STRIGIDAE 1 75 



black, with indistinct bars of buffy white; tail fuscous, with narrow 

 bars and tip of white, mottled with grayish brown ; bristly feathers at 

 base of bill dull white mixed with black ; facial disk dull buff mottled 

 with black; an indefinite superciliary line of white, with the feathers 

 dull buff at base and shaft lines of dull black; foreneck and upper 

 breast buff, with broad irregular shaft lines of brownish black, and 

 scattered edgings of buffy white ; rest of under surface, including 

 the legs, deep buff; sides and lower breast with broad shaft lines of 

 brownish black and dark brown, bordered with white to buffy white ; 

 legs spotted and barred very narrowly with buffy brown ; under 

 wing coverts buff, marked heavily with brownish black. 



Light phase : above grayish brown, below buffy white to white, with 

 markings similar to those of the dark phase, but paler. 



Juvenile, covered heavily with long, downy feathers, buff in color. 



The mottled owl is distributed throughout the Isthmus wherever 

 there is sufficient forest cover, from sea level through the Subtropical 

 Zone. It may occur in pairs, but usually singly, as they seem to 

 require a considerable area for feeding range. In daytime they rest in 

 dense cover, often in the shelter of tangles of vines. They remain 

 well hidden, and so are seldom seen. At night their abrupt calls are 

 heard, bru bru, or bu bu bu, a single note repeated two or three times, 

 with a pause of a second or a little more between each sound. 



Stomachs of those that I have collected usually have held remains 

 of orthoptera and beetles of large size. One taken near Armila, San 

 Bias, had eaten a small snake. The stomach of another from Cerro 

 Tacarcuna held a salamander. 



In young birds the wings and tail grow while the body remains 

 covered with down. Some at least leave the nest in this downy stage 

 as soon as they have any power of flight. Juvenile individuals taken 

 March 11, 1959, on the Rio Paya, Darien, and March 13, 1948, near 

 Pese, Herrera, may indicate nesting during the dry season. 



Their dark eyes give no reflection to lights during night hunting, so 

 that this owl is found seldom during such excursions. It is rare also 

 to encounter one during the day. Most of those I have handled in 

 recent years have been taken in mist nets set at night. 



Alden Miller (Condor, 1963, pp. 440-441) in studies of the syrinx 

 in owls has found that the present species has the bronchial sound 

 box considerably enlarged and elongated, so that it equals in size that 

 of much larger species of the family. The vibratile membrane is equal 



