FALCpNID/E. ARCHIBUTEO S AN C TI- J OH AN NI S . 35 



us to speak of the results of our observations and inquiries as establishing their 

 specific habits. Indeed, the European Idgopus, supposed to be identical with our 

 bird, is said to breed on trees as frequently as on cliffs. 



The marks of distinction between immature birds of this species and the Rough- 

 legged Falcon have not been so well denned as to make it possible to speak with 

 certainty of the habits of each, as given by authors. We cannot always be sure 

 which species these descriptions are meant to designate. 



The egg of the sancti-johannis of which I have the drawing measures 2 T 4 j.- inches 

 in length by l|f in breadth ; it is larger than any of the lac/opus, American or Euro- 

 pean, that I have seen, and is differently marked. The ground color is a clear cream- 

 white, and is marked, chiefly about the larger end, with dashes and blotches of a 

 light umber, and by other markings, of a deeper shade, of olive-brown. These spots 

 are each distinct, separate, and well defined, and arc intermingled with each other 

 in noticeable contrast. 



Since the above was prepared, I have been favored by Mr. John Krider, an expe- 

 rienced and well-informed ornithologist of Philadelphia, with the loan of an egg 

 obtained in New Jersey, which there seems to be no good reason to doubt is the 

 egg of this Hawk. The person who obtained it did not secure the parent bird, 

 but claimed to have had a close inspection of it, and described it as a black Hawk, 

 with other points of resemblance such as to leave no doubt with Mr. Krider that it 

 is the egg of the sancti-johannis. The nest was in a tree, and contained two eggs. 

 They varied slightly from each other in the number and depth of color of their 

 markings. The one not figured was marked more at the larger end, with darker 

 blotches, and less generally distributed. The one represented in the plate (Plate III, 

 fig. 28) measures 2^ inches in length by 1{^ in breadth. Both have many points of 

 resemblance to the drawing, yet vary considerably, most particularly in their smaller 

 size and more ovoid shape. Their ground color is a brownish or yellowish shade of 

 white. Intermixed with the ground are faint markings and blotches of a brownish- 

 purple. Over these are diffused a large number of confluent blotches of russet- 

 brown. These form a ring around the smaller end, which is undoubtedly an excep- 

 tional peculiarity. The russet-brown color may be obtained by an equal mixture of 

 burnt-umber and terra-sienna. This egg approximates very closely in its size, color 

 of its markings, and general appearance, to the egg of the A. lagopus from Switzer- 

 land referred to on page 37. 



