 Let us suppose that in any species of migratory bird, breeding can as a rule be only safely accomplished in a given area ; and further, that during a great part of the rest of the year sufficient food cannot be obtained in that area. It will follow that...  My Life: A Record of Events and Opinions - Page 393by Alfred Russel Wallace - 1905Full view - About this book
 | Popular encyclopedia - 1877 - 526 lehte
...breeding can as a rule be only safely accomplished in a given area; and further, that during a great port of the rest of the year sufficient food cannot be...will follow that those birds which do not leave the breeding-area at the proper season will suffer, and ultimately become extinct, which will also be the... | |
 | Nuttall Ornithological Club - 1880 - 288 lehte
...breeding can as a rule be only safely accomplished in a given area ; and further, that during a great part of the rest of the year sufficient food cannot...will follow that those birds which do not leave the feeding area at the proper season will suffer, and ultimately become extinct ; which will also be the... | |
 | National cyclopaedia - 1884 - 650 lehte
...given area ; and further, that during a great part of the rest of the year sufficient food cannot bo obtained in that area. It will follow that those birds...will also be the fate of those which do not leave the feeding area at the proper time. Now if we suppose that the two areas were (for some remote ancestor... | |
 | Popular encyclopedia - 1884 - 542 lehte
...breeding can as a rule be only safely accomplished in a given area; and further, that during a great part of the rest of the year sufficient food cannot...will follow that those birds which do not leave the breeding-area at the proper season will Buffer, and ultimately become extinct, which will also be the... | |
 | 1888 - 60 lehte
...breeding can, as a rule, be only safely accomplished in a given area ; and further, that during a great part of the rest of the year sufficient food cannot...It will follow that those birds which do not leave their breeding area at the proper season will suffer and ultimately become extinct ; which will also... | |
 | Alfred Newton - 1893 - 610 lehte
...breeding can as a rule be only safely accomplished in a given area ; and further, that during a great part of the rest of the year sufficient food cannot...will also be the fate of those which do not leave the feeding area at the proper time. Now, if we suppose that the two areas were (for some remote ancestor... | |
 | John Arthur Thomson - 1895 - 852 lehte
...possibility of food during winter to another country (the more southerly), we can understand, with Wallace, " that those birds which do not leave the breeding area...will also be the fate of those which do not leave the feeding area at the proper time." In short, given environmental changes of climate on the one hand,... | |
 | Conwy Lloyd Morgan - 1896 - 370 lehte
...breeding can, as a rule, be only safely accomplished in a given area ; and further, that during a great part of the rest of the year sufficient food cannot...become extinct, which will also be the fate of those who do not leave the feeding area at the proper time. Now if we suppose that the two areas were (for... | |
 | Conwy Lloyd Morgan - 1896 - 422 lehte
...breeding can, as a rule, be only safely accomplished in a given area; and further, that during a great part of the rest of the year sufficient food cannot...become extinct, which will also be the fate of those who do not leave the feeding area at the proper time. Now if we suppose that the two areas were (for... | |
 | William Jay Youmans - 1898 - 902 lehte
...given area; and, further, that during the great part of the rest of the year sufficient food can not be obtained in that area. It will follow that those...will also be the fate of those which do not leave the feeding area at the proper time. Now, if we suppose that the two areas were for some remote ancestor... | |
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