Recently published Ornithological Works. 511 



The first of these orders, the zonal, which is associated 

 with the name of Mr. Merriam, is dependent on temperature, 

 that is to say, the distribution of each form of life is limited 

 by certain extremes of temperature, especially during the 

 reproductive season. 



The second order of distribution is that very manv species 

 appear to be kept within geographic bounds by limits of 

 atmospheric humidity or the reverse. 



The third order of distributional control, the associational, 

 is dependent on local conditions — soil and vegetation 

 chiefly — which delimit the existence of a species beyond a 

 certain area. 



It is with these '' associations " that the preliminary dis- 

 cussions of this paper are mostly occupied. Mr. Griunell 

 distinguished a River association, a Willow-cotton wood 

 {Salix and Populus) association, a Tule (i. e. Reed-bed) 

 association, an Arrow-weed (Pluchea) association, and 

 Ciuail-bush [Atriplea'), Mesquite [Prosopis], Saltbush 

 { Atriplex) , Creosote (Larrefl), Cat-claw, Saguaro {i.e. Giant 

 Cactus), and finally, Encelia (i.e., Rocky Hills) associations. 



He gives lists of characteristic and exclusive birds 

 inhabiting each of these associations, which lie more or less 

 in order as one passes from the river-bed across the valley 

 to the desert country lying on either side. 



There is a long list of 150 species of birds, the distribution 

 and status of each of which is discussed in the main part of 

 the paper. 



Harterfs Pala arctic Birds. 



[Die Vo;:el der palaarktischen Faima. Von Ernst Hartert. Heft viii. 

 (Bd. ii. 2). Pp. 961-1088. Berlin (Friedlander), Aug. 1913. 4 Marks.] 



The last-issued part of Hartert's great work on the 

 Palsearctic Birds completes the Owls and commences on the 

 Accipitres, of which only one genus, Falco, containing the 

 Falcons and Kestrels, is fully dealt with. 



One interesting change is made from the commencement 

 of the Owls which certainly enhances the value of the 

 work from the systematist's point of view. This is that the 



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