192 Mr. F. N. Cliasen on the [Ibis, 



nea/as I could judge, this line crossed the mountains some- 

 where to the W. of Rupel. There was a complete absence of 

 Rooks in spring and summer — at any rate from the places 

 visited. The evening flights of Rooks on the Struma plain 

 are sometimes of stupendous size and easily mistaken for 

 genuine migratory movements. An immense flock passed 

 overhead on the 2nd of March, and the number of birds was so 

 great that for several minutes there was a noise like the 

 whirr of a sharp breeze. The movements of some flocks 

 observed in early spring would lead one to believe that there 

 is some justification for the old saying that Rooks go mad in 

 the spring. Thirty or more would separate themselves 

 from a larger flying flock and swoop towards the earth, 

 performing the most wonderful antics for a short time. 

 They would twist about, and on occasions topple over in 

 most extraordinaiy style. When the whole crowd suddenly 

 dropped to the earth, the noise was not unlike that of an 

 approaching shell. 



Corvus monedula. Jackdaw. 



This is one of the most common birds in the country, and 

 large numbers breed. Some of them paired as early as the 

 middle of February, but there were flocks about several 

 weeks later. A great deal of competition took place in 

 Macedonia for available nesting-sites. This was due to the 

 large number of Jackdaws inhabiting the country. Some of 

 them did not breed at all, and flocks composed of from six 

 to ten birds were roaming over the country, without showing 

 signs of pairing, all through the spring and summer. 

 The Jackdaws showed great adaptability in their choice of 

 nesting-sites, and within a short radius from where I was 

 living there were nests in the following sites : — In the 

 minaret of a mosque and also somewhere in the ruinous 

 roof of the same building, under the eaves of native houses 

 (otherwise unoccupied), and in holes in a steep bank. The 

 most interesting nest of all was [)laced in the lower branches 

 of a Stork's nest. The Storks and Jackdaws seemed to be 

 on the most amicable terms, but the advantages of this 



