TITS AND WARBLERS 221 



small a bird as the Chiffchaff. The Wood- 

 Warbler is also pugnacious, and will even attack 

 a pair of Chaffinches. Between the Tit family 

 and some of the smaller Warblers there are 

 constant exhibitions of hostility ; even the Great 

 Tit is liable to be driven away, but the Blue 

 Tit is especially marked out for persecution, 

 though doubtless it is well able to hold its own. 



The following incident will show how real is 

 the antagonism between these two families. 

 A ChiiFchaiF occupied the corner of a small 

 osier bed, and was particularly aggressive 

 towards other closely - related forms in its 

 immediate neighbourhood. On two mornings 

 in succession ten Blue Tits invaded its ground, 

 passing from end to end of it as they wended 

 their way from tree to tree in search of food. 

 Their presence evoked the usual hostile response, 

 yet, withal, aroused the fear of the Chiffchaff, 

 which, at times, appeared to be swayed by 

 conflicting impulses. Now, in attempting to 

 interpret the nature of the instinct which was 

 evoked, one has to be guided, in a case of this 

 description, by the similarity of the response to 

 that which can be observed on other occasions 

 and in other situations when the intention of 

 the bird is clear. And on this occasion the 

 Chiffchaff betrayed all the symptoms which 

 normally precede an attack ; it spread its tail, 

 quivered its wings, uttered its high-pitched note 

 rapidly, hopped from twig to twig, or flew 

 restlessly from tree to tree, and seemed to be 

 prevented from attacking only by the number 



