ORIOLE INSTINCT. 



By J. A. MuNRO, Okanagan Landing, B.C. 



Mr. Taverner's note in the May issue, describing 

 the nest built by a pair of young orioles, recalls an 

 experience with a nesting pair of the Bullock's 

 Oriole, in the summer of 19n. As in the case of 

 the pair Mr. Taverner had under observation, the 

 male was a bird of the previous year and it was 

 taken for granted that the female was also. 



The writer was camped under a group of quaking- 

 aspens on the shore of Okanagan lake and in one 

 of these trees the orioles had started building. The 

 branch to which the nest was fastened was an upright 

 one, half an inch in diameter, close to the top of the 

 tree and some twenty feet from the ground. Atten- 

 tion was drawn to the partly constructed nest, by the 

 efforts of one of the birds to draw out a linen thread 

 from a bath-towel, hung over a wooden railing near 

 the nesting tree. With the end of the thread held 

 in the bill and with feet braced against the railing, 

 the bird tugged and worried at the thread until it 

 became loose; then with one decisive jerk, flew with 

 it to the nest. This was repeated several times ; an 

 inexhaustible mine of building material had been 

 found. 



Having often read of the oriole's instinctive re- 

 jection of colored string for nesting material, it was 

 thought to be a good opportunity for experiment 

 along this line. Accordingly an assortment of 

 various colored yarns, white, pale blue, red, black 

 and pink were cut into convenient lengths and placed 

 in a row on the bath towel. In a few minutes the 

 female returned to the towel-rack and findmg this 

 loose material, a new treasure-trove on top of her 

 linen mine, mad; no attempt to pick out more 

 threads as long as the white yarn was available. The 

 colored yarns were not touched and when the supply 

 of white was exhausted, the towel again came in for 

 attention. The reputation of the species for sagacity 

 seemed to be established. 



She worked most industriously, taking, on an 

 average, five minutes to weave into the nest a piece 

 of yarn twelve inches in length and a minute or a 

 little longer to return and select another piece. Be- 

 fore alighting on the towel-rack she always gave the 

 characteristic harsh call-note. 



The female did most of the building; indeed it 

 was not certain that the male performed any of the 

 work; their similarity, and the fact that they did not 

 appear together, made it difficult to recognize the 

 sexes. 



Anxious to discover if this instinctive selection of 

 neutral-colored material would operate under more 

 complicated conditions, the colored yarns were 

 collected and to each of them was knotted a piece 

 of white yarn of the same length and they were 

 placed again on the towel rack, with the white por- 

 tion uppermost. Without hesitation she began carry- 

 ing off the pieces, with the white portion held in her 

 bill; the white half was woven into the nest and the 

 colored half allowed to hang from the outside. 



Oriole instinct was at a discount now, and I 

 became bolder in my experiments. Selecting some 

 soft thick yarns, in red, green and black and, when 

 fluffed out, of the diameter of a pencil, I tied these 

 in twelve inch lengths to short pieces of fin; white 

 yarn. These were taken as quickly as the last; the 

 short ends of white woven into the fabric of the nest 

 and the larger colored portion allowed to hang from 

 the outside. It was amusing to see the bird fly into 

 the tree with a long brilliant streamer trailing behind. 



The nest was now ablaze with color, long gaudj' 

 strands hung from all points, six to ten inches below 

 the bottom. To add to the color-scheme I tore into 

 strips, a necktie of a particularly violent pattern in 

 red and green, and tied on the usual piece of white 

 yarn. The bird was now utterly demoralised and 

 did not balk at this singular adornment. Several 

 pieces were added to the upper part of the nest. 



The polychromatic structure was now completed; 

 the eggs were laid and the nestlings raised without 

 mishap, while the decorations waved in the breeze 

 to the wonder of the passerby and perhaps the con- 

 fusion of marauding, egg-hunting crows. 



A closer examination of the nest after the young 

 had flown, revealed the fact that it was of unusually 

 poor workmanship, loosely made from various kinds 

 of string, through which was woven, the white yarn ; 

 the shght lining was of black horsehair; no roots or 

 other fibrous material had been used. 





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