Vol ‘i924 IV ’] LEWIS, Mutton-Birds of Phillip Island 
87 
requires a clear area in which to gather speed before rising. Any 
obstruction such as grass or other growth seems to prevent the 
birds from leaving the ground. 
EXPERIMENTS REGARDING THE RETURN OF BIRDS 
DURING THE SEASONS 1920—1923. 
Sixteen burrows were selected and numbered in 1920, and the 
adult birds found therein were banded. In 1920 coloured cellu¬ 
loid rings were used, but in 1921, 1922, and 1923, soft metal 
rings with a number stamped thereon were utilised. As a result 
of these markings, it has been proved that many of the Mutton- 
birds return to the same burrow, or adjacent ones on the same 
rookerv, in some cases with an unmarked mate, but some¬ 
times the same pair will return to the same hole. In 1920 
sixteen birds in twelve burrows were marked with celluloid rings. 
In 1921 four of these burrows were not used by the birds. 
Amongst ten birds examined from the remaining burrows, it 
was found that six had returned to their old burrows; in one 
case a pair of marked birds was found in the burrow used the 
previous year. In 1922 four marked birds returned, two of these 
being an original marked pair, while another pair marked in 
1920 was found in an adjoining burrow. In 1923 four marked 
birds again returned to the same burrows, while the pair in the 
adjoining burrow also came back. Another marked bird was 
found in a neighbouring burrow. Summarised, the results from 
the 1920 markings show that, over a period of three years, ten 
out of sixteen birds returned to their old holes, while one re¬ 
turned to a burrow near its original hole. Two original birds, 
marked in 1920 returned to their old home. In 1921, twenty-two 
birds were marked with metal rings in twelve burrows. In 1922, 
eight of these returned to their original holes, and one was found 
in an adjoining burrow. Two of the returned birds were an 
original pair. In 1923 seven birds returned, two being an 
original pair, and four others were found in adjoining holes. 
Summarised, the 1921 markings show in two years a total return 
of ten birds out of 22 to their original holes and five to adjoining, 
holes. Two original pairs of birds returned, one pair for two 
consecutive years. 
Out of 44 birds marked, 22 have been shown to return to their 
original holes in the different seasons and six others have been 
found in adjoining holes. No search was made for the marked 
birds in holes any distance away. As the rookery where the 
selected holes were situated is approximately 400 ft. square, and 
contains some 500 holes closely packed, it is remarkable that 
such a percentage of the birds should return to their original 
holes. It would seem, therefore, that once a bird has laid 
its egg in a particular rookery, it does its best to return to 
that same rookery every year. 
An instance of the homing instinct of the birds may be quoted. 
Across a pathway leading to the camp of the observer was 
