40 FALLA, Breeding of Butlers Shearwater. [ 7st juT y u 
is slightly larger, although they vary considerably in size. This 
is also the case with the eggs of Buller’s Shearwater taken, on 
the Poor Knights (see plate), but a glance at the measurements 
given later in this paper will show them all to be much larger 
than the Mokohinau example mentioned by Bent. Lastly, we 
found on the Poor Knights that Buller’s Shearwater does not lay 
until December, a habit which it shares with only one other 
Shearwater in this breeding area, the Fleshy-footed (Puffinus 
carncipcs ). A brief account of our investigations follows. 
Under weather conditions which were little short of ideal, we 
landed on December 23rd, on the smaller and southernmost of 
the two main islands. This island is somewhat conical in shape, 
and on all sides except the north, rises in an abrupt slope from 
the sea. Near our landing place on the northern end, a heavily 
wooded valley gave easier access to the central peak. Much of 
this vegetation is second growth and covers the remains of ex¬ 
tensive native cultivations and fortifications, although it is con¬ 
siderably more than a century since the last of the inhabitants 
were massacred by a war party from the mainland. This one 
island of the group supports a few wild pigs, undoubtedly de¬ 
scendants of the original “Captain Cookers/' and these animals 
take heavy toll of young Petrels, a large indigenous snail 
(P la costylus hongii), and of young plants. Progress through 
the skirting belt of flax (Phormium tenax ) was slow, and through 
the low-growing scrub on the steep slopes still slower, but we 
had not gone far before we were able to recognise among the 
remains of birds which the pigs had rooted out of the burrows, 
several wings and other parts of Buller’s Shearwater. Further 
inland, in the larger bush towards the summit, the victims of the 
pigs’ depredations were Dove Petrels (Pachyptm turtur). During 
several hours’ stay on this island no living Petrels of any kind 
were found, and all the burrows examined were empty. 
On the following day, December 24th, a landing was effected 
on two of the outlying islets, and later, on the largest and north¬ 
ernmost island, which differs from the others in being more 
precipitous, but flatter on the top. The vegetation here is de¬ 
scribed by Dr. Cockayne as “meadow.” This consists for the 
most part of large areas of a wiry coast grass (Poa anceps) and 
pig-face (Mesembryanthemum australe) interspersed with clumps 
of stunted pohutukawa (Metrosideros tomentosa), flax bushes 
(Phormium tenax) and the waving tufts of toi-toi (Arimdo 
conspicua). Several areas of low forest, invisible from the sea, 
also occur on this northern island. Here, free from all danger 
of pigs, the birds were nesting undisturbed. The first burrow 
examined, on an islet on the eastern side of the group, was about 
twelve feet above high-water mark, in hard soil, underneath a 
ledge of rock. It was only two feet in length, and the bird could 
be seen sitting head inwards. Unlike several handled later, she 
