MIGRATION. 
397 
north on the first approach of winter. Thus, we see, 
they are governed by much the same laws as our own 
birds of passage. 
The “passage” in many respects resembles the second 
and partial migration before mentioned.* This may be 
especially remarked in the case of those birds which are 
obliged to descend from the mountains to the lowlands 
on the approach of winter, returning to the highlands 
again in the spring. In our part of the world these may, 
without exception, be classed with the second and third 
class of migrants.! In the southern districts of America, 
and probably to a certain extent in India, they become 
veritable birds of passage. According to D’Orbigny we are 
told that every year at the same season, when the true 
South-American birds of passage take their departure, all 
the different Thrushes, Starlings, Warblers, Flycatchers, 
Swallows, Goatsuckers, Kingfishers, and others, leave 
the heights of the Southern Andes for the low ground; 
those inhabiting the southernmost portion of the range 
moving south and north; and those occupying the 
mountains lying to the northward shifting chiefly west 
and east of their real home, some even reaching the low¬ 
lands along the coast of the Pacific. The regularity of 
their journeys in respect of season and direction is such 
that they can scarcely be counted among the wanderers of 
the second class, but much rather resemble the true 
migrants. None of these birds ever breed in the lowland 
districts, or are to be found there during the nesting 
season; in short, their whole conduct is identical with 
that of the true migrants. In the north of the Andes the 
* The three classes of migration understood in German under the following 
terms—Zug, Wandern, and Streichen—have no distinct rendering in English, and 
are but expressive of one action—migration—in three degrees of intensity.— W. J. 
+ German :—Wandern and Streichen.-— W. J, 
