140 THE POPULAR SCIENCE MONTHLY 
in natural cavities, and when the entrance is large regularly blocks the 
passage with mud until it will barely admit her body. The hornbills 
have possibly lost the cleaning instinct, if they were ever possessed of it, 
and the singularity of their present activities must be attributed to in- 
stinct alone. 
The little honey-guides are related to the barbets, and hoopoes, 
rather than to cuckoos, although like many of the latter they are thought 
to regularly steal the nests of other birds, and never rear their proper 
young. But aside from this diversion, they are said to conduct the pass- 
ing traveler to bees’ nests, to call his attention to the important busi- 
ness in hand by hisses and shrill cries, and to even fly in his face “as 
if enraged at not being followed.” ‘That such efforts are not wholly 
altruistic may be gathered from the fact that they will eat the bees, 
grubs and honey alike. According to the accounts, the honey-guides 
are the “pointers” among birds, for when the woodsman is encoun- 
tered, they flutter up to him and point the way to a nest, and if fol- 
lowed, go on and on, but halt when hot on the trail. They will also 
point to empty nests, or even to a domestic hive, but more significant 
than this, they will follow a dog, or lead the confiding traveler to a 
leopard, cat or snake, showing clearly that, whatever the origin of this 
practise, whether concerned with the instinct to sound the alarm at a 
common enemy, and to follow it and keep it in view, or not, we are 
dealing with an instinct; and probably one of very pure type. 
We will close this account by giving one or two reputed instances of 
bird-intelligence which stand out in a marked degree from others of 
their kind, on account both of the acts themselves and the credibility 
of the witnesses. Thus Montagu, whose excellence as an observer is 
abundantly proved in his “ Ornithological Dictionary of British Birds,” 
states that he once saw two crows (Corvus corone), by the seashore 
“busy in removing small fish beyond the flux of the flowing tide, and 
depositing them just above high-water mark, under the broken rocks, 
after having satisfied the calls of hunger.” It seems to me that too 
much has been made of this instance, since it may with equal justice 
be interpreted as an illustration of the instinct to hide, the circum- 
stance of the tide being fortuitous, for it does not follow that these 
birds knew that the tide would surely advance and sweep away their 
prize. The incident, however, is interesting in relation to another, told 
of the hooded crow (Corvus splendens), by the worthy Blackwall, who 
saw these birds “on the eastern coast of Ireland, after many unavail- 
ing efforts to break with their beaks some of the mussels on which they 
were feeding, fly with them to a great height in the air, and, by letting 
them fall on the stony beach, fracture their shells, and thus get posses- 
sion of the contents.” Perhaps it would not be easy, says Blackwall, 
“ to select a more striking example of intelligence among the feathered 
o 
