324 Recently published Ornithological Works. [Ibis, 
Shrikes, and many other families may be quoted as be¬ 
longing to the former. Some of the communal breeders 
have also adopted a system of communal defence (more 
especially the Terns), but with others nothing of the kind 
has yet been evolved. 
We think a truer idea of Territory in Bird Life would be 
gained by eliminating the actual nesting-site, which is, 
of course, a necessity in every case, and restricting the 
use of the word to the area embraced by the activities of 
the parents. We shall then find that in some groups all 
other individuals of the same species are rigidly driven off 
the whole territory, in others the idea is only present in a 
rudimentary form, and in a third class the association is of 
the closest kind and individual territory is unknown. 
There is also a wide field for research, untouched in the 
present work, on the occasional unresented presence of a 
third individual together with a pair in the case of a nor¬ 
mally monogamous species. Probably this has been noted 
most frequently in the case of the Long-tailed Tit, but 
there are recorded instances in some twelve or fourteen 
other species at least. We are grateful to Mr. Howard for 
his beautifully illustrated and thoughtful study on an aspect 
of bird-life, which by his researches he has undoubtedly 
done much to elucidate.—F. C. B. Jourdain. 
Hellmayr’s recent papers on Neotropical Birds. 
[Ein Beitrag zur Ornithologie von Siidost-Peru. Von C. E. Hellmayr. 
Arch. Naturgesch. Jahrg. 85, Abt. A, 1920, pp. 1-131.] 
[Miscellanea Ornithologica, V. Id. Verhandl. Orn. Ges. Bayern, 
xiv. 1920, pp. 281-287.] 
The first of these papers contains an account of the more 
interesting forms contained in a collection made by the 
brothers H. and C. Watkins in the Department of Puno 
in south-eastern Peru, near the Bolivian border. These col¬ 
lections reached Europe before the outbreak of the war, 
and are now preserved, partly in the Munich Museum, 
partly in the private collection of Count Josef Seilern. 
