From April, 1985 to March, 1986, Black-headed Gull Larus ridibundus, Bonaparte's Gull L. philadelphia (a straggler), Herring Gull L. argentatus, Slaty-backed Gull L. schistisagus, Black-tailed Gull L. crassirostris and Mew Gull L. canus were observed at the mouth of Tama-river, which forms the boundary between Tokyo-Metropolitan and Kanagawa Prefectures. The main species were Black-headed and Black-tailed Gulls in this estuary. The Black-headed Gull was dominant in winter whereas the Black-tailed Gull replaced it from July to September. Other four species occurred only in small numbers.
The homeostasis (Cannon, W. B. 1932) denotes the "dynamic stability" widely applicable in biological phenomena of physiological (originally proposed by Cannon), morphological, ecological, genetic, as well as developmental aspects. Its mechanisms are related with all sorts of intrinsic adaptive inter-relationships among parts and between parts and whole (endoadaptations), under extrinsic influential factors (exoadaptations). The homeostasis comprises mechanisms of "balance" (phenomenal stableness), "equilibrium" (functional stability), "compensation" (adaptive organic relations), and "stability" (constancy under varying external factors), and it involves self-regulatory mechanisms which contribute to the persistence of dynamic stability. It also involves the developmenal "genetic canalyzation or assimilation" of Waddington (1942), and evolutionary "stabilizing selection" or "stasigenesis" (Schmalhausen 1941) as well as "normalizing selection" (Waddington 1942), and functional "rationalization" (Rensch 1960). In this paper, the homeostasis is discussed under the items of: 1. Physiological homeostasis (originally by W. B. Cannon, 1932, "The wisdom of the body") 2. Genetic homeostasis (to be referred to Lerner, 1954, "Genetic homeostasis") 3. Genetic stability (Hardy-Weinberg law, 1908) 4. Homeostasis in population genetics (cf. Mayr 1963) 5. Genetic inertia (Darlington & Mather 1949) 6. Morphological homeostasis (cf. Rensch 1960, Mayr 1963, Kuroda 1954, "character-complex", "habit-forms", "compensatory adaptation" etc.) 7, 8, 9, Ecological homeostasis (various aspects, to be referred to Trojan 1984, "Ecological homeostasis") 10. Homeostasis of coexistence (exemplified by birds vs. mammals) 11. Homeostatic aspects in human society as compared with animal world 12. Climatic homeostasis (dynamic stability of short and long term climatic cycles).