NORTHERN CLIFF SWALLOW 465 



One thing is apparent : as the land of New England was cleared 

 for fields and pastures, and as barns with wide eaves were erected, 

 the cliff swallows, finding an abundance of food and sheltered places 

 for their nests, left their primitive environment of isolated cliffs to 

 come in close association with man. Under these new conditions the 

 birds multiplied and spread from place to place where they had not 

 been seen before. It is also possible that there was an eastward 

 movement later from the cliffs and bluffs of the West, but for this 

 there is no concrete evidence. 



In more recent years the prosperity of the cliff swallows in their 

 newly acquired environment has suffered. Such factors as the in- 

 vasion of English sparrows, the improvement and painting of barns, 

 and the desire of owners to rid their buildings of the mud nests 

 have affected the local fluctuations in the number of these valuable 

 and attractive birds. 



So serious was the decrease of these birds in New Jersey where 

 formerly they were abundant that the New Jersey Audubon Society 

 under the leadership of W. DeWitt Miller proposed a campaign by 

 the society for increasing the summer resident cliff swallows in New 

 Jersey (Bowdish, 1930). Miller considered modern barns offering 

 poor support for nests and molestation by thoughtless boys and 

 men as factors contributing to the decrease. The plans of the society 

 were announced in its bulletin and made public through news items 

 sent to the press. A survey of nesting colonies was made, and sug- 

 gestions, such as nailing plates to the ends of the rafters of barns to 

 afford more dependable supports for the nests and providing a readi- 

 ly available mud supply, were made. The value of the swallows was 

 also impressed on owners of buildings where colonies were located. 

 Furthermore, prizes were offered for the three largest colonies. I 

 have seen no reports of the effectiveness of the campaign, but it is at 

 least an interesting project in connection with the history of this 

 species. 



Spring. — The first cliff swallows reach northern Mexico and our 

 Southwestern States during the last week of March. From this region 

 the wave of migration is exraordinary from the standpoint of its 

 speed up the Pacific coast and its lag in the southeastern part of the 

 United States. It has long be^n known that the earliest records 

 always come from California where it usually becomes common long 

 before it has been observed in Texas, the Gulf States, and Florida. 

 By March 20, when the vanguard has not quite reached the lower 

 Rio Grande in Texas, the species is already north of San Francisco, 

 Calif. Lincoln (1939) presents a plausible explanation of this ornitho- 

 logical puzzle by pointing out that the cliff swallow goes 

 around the Gulf of Mexico rather than across it. He states further: 

 "The reason for this circuitous route around the Gulf of Mexico lies 



