162 BIRDS OF TUNISIA 



with grey shell- marks, and rufous or- claret-coloured surface-spots and 

 blotches. The average measureiuents are 60 x 45 mm. 



Eggs are generally to be found towards the latter part of April. 

 In some parts of America the Osprey breeds in colonies, but it never 

 seems to do so in Europe. 



Both Loche and Erlanger have alluded to the possibility that the 

 Osprey found in North-west Africa may prove sufficiently distinct 

 from typical P. halia'etus to merit separation, in which case it 

 should be referred to P. alhigularis, Brehm (Vogelfang, p. 12). The 

 reasons for any separation, even subspecific, appear, however, to be 

 insufficient, and such an authority on the subject as Mr. Gurney 

 considers that there is but one species of Osprey. 



