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AMERICAN FORESTRY 



instinct of fear is strong. Birds that are impossible sub- 

 jects while incubating or brooding newly hatched young 

 are nearly fearless as the young leave the nest. The 

 yellow-breasted chat is a good example. It has proven 

 a stumbling block to photographers for twenty years, 

 because all of its instincts are subservient to that of fear 

 or caution. It will desert its nests and even its young 

 upon the slightest provocation, so that it is practically 



A SOCIAL VISIT 



This family of rough-winged swallows is entertaining a visitor with whom thev 

 appear to be on most cordial terms. The writer wonders if this is the beginning 

 of a social instinct among birds. 



impossible to secure a photograph of it. When the young 

 are leaving the nest, however, the instinct to feed and 

 protect them reaches its highest point, nearh' balancing 

 the bird's fear, so that during the past summer it was 

 possible, with the exercise of sufficient caution, to secure 

 some photographs of the male bird feeding the young. In 

 the case of the robin, then, the flight of the voung from 

 the first nest aroused in the second female the more 

 powerful instinct and she deserted the newly hatched 

 young to care for the fledglings, even though they were 

 not her own. 



Observation of unusual cases such as this one of the 

 robin is often suggestive of the origin of inexplicable 

 habits among some species of birds. For example, many 

 members of the wren family, including both species of 

 marsh wrens, the house wren, the winter wren and at 

 least three species of South American wrens and probably 

 others, build duplicate nests. These have been variously 

 called " cock nests," " dummy nests," etc., but thev have 

 never been satisfactorily explained. The house wren, for 

 example, fills every hole and every nesting box in the 

 vicinity with sticks before commencing the actual nest 

 that is to be used. The marsh wrens build six or seven 

 nests within a short radius, only one of which is used. 

 The winter wren does the same, although, because of the 

 nature of its nesting site, the various nests are farther 

 apart. In each case the nest building does not cease 

 with the completion of the real nest but continues through- 

 out the season and it is not uncommon to find marsh 

 wrens still building, after the middle of August, nests 

 which will never be used. The explanation for this 



curious over-development of the nest-building instinct is 

 difficult to see but careful observation of a large number 

 of cases may shed some light upon it. The case of a pair 

 of house wrens which built upon my porch is particularly 

 elucidating. 



The male bird, as usual, appeared first in the spring 

 and immediately began filling all of the nesting boxes in 

 the vicinity with sticks. Other males that appeared were 

 promptly driven oft". After a few days a female appeared 

 and remodelled and completed the nest which the 

 male had started in the box on the porch, the male 

 helping her at intervals but also continuing to carry sticks 

 into other boxes. By the time the complement of seven 

 eggs was completed, we discovered another pair of wrens 

 nesting over a neighbor's door, but soon afterwards 

 observed that the two males were never singing at the 



^^^7€^- 



CAN YOU SEE HIM? 



A song sparrow on its nest, well hidden from prying eyes and from enemies 

 because it is streaked like the grasses which it inhabits and seems a part of them. 



same time and began to suspect that something was 

 wrong. At this time our male got caught in a sparrow 

 trap and we placed an aluminum band on his leg to mark 

 him. Identification was now comparatively simple and 

 we easily followed the bird from one nest to the other. 

 It was obviously a case of polygamy. An even stranger 

 part of the story follows : 



Thirteen days after the laying of the last egg. we 

 looked into the box in the morning and found the young 

 hatching. Two days later, when we came home at noon, 

 we found the male bird throwing hair and feathers out of 

 the nest and every young had disappeared. It was evi- 

 dent that the young had preceded the feathers and that 

 the father of the family was on the rampage. We 

 hastened to the neighbor's nest expecting to find another 



