RECENSIO CONTRADICTORIA. 



Order of : Land Birds travel without distinct order, others in < 

 order, one side being longer. EMPhROR Fredfric. 13. Separately 

 according to age; in spring old ones arrive earlier, in autumn young 

 ones depart earlier. Gatke. 11. ^ There exists a successive and by- 

 passing Migration. Palmen. 11. — There is a head-, main-, and rear- 

 part. HOMEYER. 6. 



Restingplaces on : A certain quartering system is observed by 

 wandering Birds. Brehm Ch. L 13. — Along the migration route 

 there are certain places for rest. Naumann. 3. — There are regular 

 and irregular resting-stations. Homayer. 11.-- On the way Birds stop 

 at quite inappropriate places. Severtzoff. 2. — Over unfavourable 

 districts Birds pass without a break. Palmen. 8. 



Routes of : Birds migrate from colder regions into warmer ones and 

 vice versa — passagium et reditus. Emperor Frederic. 1. In both 

 seasons not the same. Gatke. 3. — The spring and autumnal Migra- 

 tion not always on the same route. Menzbier. 6. — There are certain 

 recognized routes or highways of Migration. Brehm, Ch. L 12. — 

 Naumann. 1. — Middendorff. 1, 2. — Weissmann. 5. — Palmen. 3. 



— Martorelli 17. — Menzbier. 1. — Each species travels by its 

 own route. Severtzoff. 1. — Tristram. 4. — Menzbier. 2. Mig- 

 ration routes are the history of the distribution of the species. Menz- 

 bier. 5. — There are Migration-routes. Homeyer. 1. - Gatke. 12. 



— Migration-routes scarcely exist. Kessler. 10. 



Time of : There is a spring and an autumnal Migration. Gatke. 

 1,2. — Smaller birds wander at dusk, large birds during the day, 

 strandbirds at night. Homeyer. 4. 



Orientation, inherited sense of orientation Weissmann. 7. — Tra- 

 ditional heredity. PALMEN. 13. — Is not infallible. Martorelli. 18. 



Original home (Cfr. also Breeding places p. 87.) The Tropics, 

 from whence emigration northward took place. Deichler. 4. — 



mi ()1 "SSI 



