Expedition to the Zambesi River. 581 



and I have frequently witnessed an example of this when 

 a Hawk lias been hovering over the reed-bed haunt of 

 this bird. Besides the call-note, the male bird utters a 

 remarkable love-cry. With a sharp clapping together of the 

 wings, a soft clarion-like whistle is given out, followed 

 immediately by a very peculiar note, in sound just as Avhen 

 a hammer is tapped against a sheet of tin. As the season 

 advances this whistle becomes cracked and less clear in 

 tone. 



This Shrike is full of activity. He will wend his way 

 through a maze of thick twigs and run up the limbs of a tree 

 with extraordinary jigility, his head all the while strained 

 forward with anxious look, as if he were fleeing from some 

 invisible foe. Although he is of a quarrelsome nature, 

 and is continually worrying other members of the bird- 

 fraternity that frequent the same thicket as he does, yet 

 they seem to tolerate him, since he never fails to warn them 

 of approaching danger by uttering his frog-like notes of 

 alarm. More than once has this bird deprived me of a 

 fine specimen that was almost within my grasp. The 

 food is varied. The small Estreldas that thread their way 

 through the reeds and thickets are often attacked and 

 become his prey. 



We obtained a fine series of this Shrike, both immature 

 and adult. In two fully adult specimens the white on the 

 secondaries is confined to only one of the wing-feathers; 

 in the immature birds the white is sometimes on two or 

 three of the secondaries, and in one instance the third 

 white stripe is in the process of disappeai'ing. Again, the 

 adults have no white tips to the outer tail-feathers, while all 

 the others possess them. We are therefore of the opinion that 

 the number of the white stripes on the wing-feathers is of no 

 specific value, and that the number decreases with age, while 

 it is quite possible that in very old birds the wing-feathers 

 become entirely black. To the same cause may be attributed 

 the disappearance of the white tips, which in very young 

 birds are huffish white, to the outer tail-feathers. Further- 

 more, in the series before us, we find that the huffish tints 



SER. VII. VOL. V. 2 R 



