CUCULUS CANORUS. 517 



birds (which is rather an unusual thing for their kind) are feeding them 

 regularly. The mellow notes of the old birds are to be heard frequently 

 during the day.— May 18th, 1889. 



Another instance was recorded from Midlothian. Yet in 

 spite of these the Edinburgh papers held that the cuckoo never 

 hatched its own eggs. One writer says — 



" I see from the public prints that Professor Muller says he knew of a 

 cuckoo that did so. I have not seen the date, therefore cannot give the 

 Professor's facts. I merely mention this very rare — perhaps hitherto 

 unknown — instance of incubation by the cuckoo." 



Another writer said — 



"None of us are too old to learn, but I am too old a bird to believe on 

 the mere assertion of a single man, however eminent that man may be." 



This question — " Does the cuckoo ever hatch its own eggs ?" 

 — was going on at the very time these instances were recorded, 

 which makes the question interesting, if not perplexing. I am 

 sorry I did not go to Mr Eobb, at Horselaw, and see the 

 cuckoo's nest with eggs or young, for I believe in its truth, as 

 there is no law in Nature so absolute (in connection with birds 

 and their eggs) that cannot be varied. At one time it was 

 thought an internal impediment prevented the cuckoo from 

 incubating — now exploded. During the discussion the fact of 

 placing its egg in the nest of other birds by the mouth was 

 clearly demonstrated. An "Auld Herd Laddie" 



" Saw the cuckoo place her egg by the mouth into the heather linnet's nest 

 when mobbed by the excited linnets, trying to make her drop her egg. 

 When the deed was done they all at once left, some of them so exhausted as 

 not to be able to fly any distance. He once saw the heather linnets succeed 

 in making the cuckoo drop her egg and break it. They all at once left 

 before they had time to see if it was broken or not, leaving the cuckoo 

 sitting alone, crying her well-known note, which she could not do while 

 they were teasing her with the egg in her mouth. He went to the spot and 

 found the broken egg he saw her drop." 



I think the " heather linnets" were meadow pipits. He asks 

 some pointed questions — " Can any of your readers tell me how 

 the heather linnets know when the cuckoo has an egg in her 

 mouth ready to deposit it into one of their nests, as they do know, 

 without a doubt ? Also, How does the cuckoo know where the 

 heather linnet's nest is, so as to get her egg deposited ? When 

 a boy these were puzzles to me. Your readers may think she 

 found it out beforehand, but I doubt that. Did any one ever 

 see a cuckoo looking for nests 1 From what I have seen I think 

 the linnets, in their extreme anxiety to protect their nest, lead 



