Growth and development peculiarities of the Little Egret, the Grey Heron and the Night Heron. - A.A. Tkachenko. - Berkut. 3 (2). 1994. P. 96-99.
Particular features of nestlings' growth and development of 3 heron' species were researched in the mixed colony on the Gorodki Island (Dneprodzerzhinsk reservoir on the Dnieper). 2 groups of 15-25 nestlings for each species were maintained: experimental
group bringing up in captivity and the same control group in the colony. Nestlings of all species develop similarly. Specific growth velocity is higher in the first 3-6 days (0.2703-0.2824), then it gradually drops up to as 17-19th days by the Little Eg
ret and Night Heron and as 22-25th days by the Grey Heron. Further, specific growth velocity sonic increases (0.0297-0.0862), afterwards it decreases up to 0-0143-0.0180 before the flying out of fledglings. Basing on the data about changing of the Growth
Constant (K), it is possible to divide all period of the development on 5 phases: 1) the minor increase of the body mass during the first days of life (K < 0.8); 2) the first increasing of the growth intensity with K = 1.3-1.8; 3) delay of the growth co
nnected with feather's development by nestlings (K = 0-014); 4) the second increasing of the growth intensity (K = 0.85-1.94); 5) gradually decreasing of the intensity of nestlings' body mass before their flight (K = 0.3-0.8). Necessary energy for growth
of nestlings' body mass on 1 g is 34.1 kJ for the Little Egret, 33.8 kJ for the' Grey Heron and 28.2 kJ for the Night Heron. At the same time utilisation coefficient grows in the row Little Egret - Night Heron - Grey Heron This leads to, that nesting pe
riod is comparatively shorter by large species, than by little ones. [Ukrainian].
Key words: Little Egret, Grey Heron, Night Heron, growth, development, energy, metabolism.