The position of the nest is quite characteristic
Il1 warbler species. Nearly all species of the genus
Dendroic« nest off the ground. Figure 8 shows heights of the nests of the five species of warbler studied here. These data result from a combination of the records of Cruickshank (1956), the information in the egg collection of the American
Museum of Natural History in New York, and
that gathered in this .study. Since the distributions
are skewed and irregular, the median and confidence intervals for the median (Banerjee and Nair 1940) are appropriate measurements. As the
figure shows, the Cape May, with 9570 confidence
interval for the median of 40-50 feet, and the black
burnian, whose interval is 30-50 feet, have quite
similar nest heights, probably reflecting their tendency to feed at high elevations. The Cape May's nest is virtually always near the trunk in the
uppermost dense cluster of branches in a spruce
or occasionally a fir. The black burnian may nest
in a similar location or may nest farther out toward
the branch tips. Myrtle and black-throated green
have similar nesting heights, both species having
95% confidence interval for the median nest height
of 15-20 feet. The black-throated green seems to
prefer smaller trees for its nest, and is thus more
likely to place its nest near the runk, but, in
keeping with its other characteristics, the myrtle
seems quite varied in this respect. Finally, the
bay-breasted, which has the lowest feeding zone,
has the lowest nest position, the median height
being between 10 and 15 feet (9570 confidence).
Thus, the nest positions of the five species of
warbler reflect their preferred feeding zones.
The position of the nest is quite characteristicIl1 warbler species. Nearly all species of the genusDendroic« nest off the ground. Figure 8 shows heights of the nests of the five species of warbler studied here. These data result from a combination of the records of Cruickshank (1956), the information in the egg collection of the AmericanMuseum of Natural History in New York, andthat gathered in this .study. Since the distributionsare skewed and irregular, the median and confidence intervals for the median (Banerjee and Nair 1940) are appropriate measurements. As thefigure shows, the Cape May, with 9570 confidenceinterval for the median of 40-50 feet, and the blackburnian, whose interval is 30-50 feet, have quitesimilar nest heights, probably reflecting their tendency to feed at high elevations. The Cape May's nest is virtually always near the trunk in theuppermost dense cluster of branches in a spruceor occasionally a fir. The black burnian may nestin a similar location or may nest farther out towardthe branch tips. Myrtle and black-throated greenhave similar nesting heights, both species having95% confidence interval for the median nest heightof 15-20 feet. The black-throated green seems toprefer smaller trees for its nest, and is thus morelikely to place its nest near the runk, but, inkeeping with its other characteristics, the myrtleseems quite varied in this respect. Finally, thebay-breasted, which has the lowest feeding zone,has the lowest nest position, the median heightbeing between 10 and 15 feet (9570 confidence).Thus, the nest positions of the five species ofwarbler reflect their preferred feeding zones.
การแปล กรุณารอสักครู่..