226 THE BIRDS OF NORTH A3IPT0N SHIRE 



the inquisitive Harriers, of which family two species 

 were very abundant, and both of them extremely 

 addicted to egg-stealing. 



From my own observation of the present species 

 and its close congeners I am convinced that a very 

 great part of their food consists of winged insects 

 taken in the air, but leeches are also very favourite, 

 and in Spain, at least, very abundant " tit-bits " ; 

 whilst, no doubt, heavy contribution is also levied on 

 the minute fry of fishes and frogs. The cry of 

 the Black Tern is a shrill creaking monosyllable 

 constantly repeated. This bird was formerly well 

 enough known in some English counties to gain the 

 somewhat rare distinction of a local name, such as 

 " Blue Darr " in Norfolk, " Car-Swallow " in Lincoln- 

 shire, and "Starn," "Dare," and "Skelper" in other 

 places. Out of England and Spain I never met with 

 this species in any considerable numbers ; but it is 

 by no means uncommon on passage throughout the 

 western basin of the Mediterranean, and I met with 

 it in spring on the lake of Geneva. 



201. COMMON TERN. 



Sterna fluviatilh. 



As I have stated at the commencement of the 

 previous article, Morton's note concerning this species 

 ("the Sea-Swallow") is still applicable wdth regard 

 to its visits to our neighbourhood, but I believe that 

 it is very frequently to be seen very much further up 

 the Nen valley than Thrapston, the highest limit 

 assigned to it by our old naturalist. At all events, 

 I have myself seen a few of these birds from the 



