Heat Production of Goldfinches and Canaries in Summer and Winter 103
occurred at ambient temperature of 29.2 °C in winter and of 33.6 °C in
summer. In winter canaries at ambient temperature of 36.1 °C panting
occurs, whilest in summer canaries at 37°C. These results confirm earlier
observations on birds [4, 5].
2. Basal Metabolism
By analyzing BMR obtained at neutral temperatures, we find that BMR
appears in winter at 30°C environmental temperature, after a stay of appro
3-4 weeks at -6 to + 8 °C; in summer it occurs at 33°C, if the birds are
living at temperatures between 23 and 28 0C. The neutral temperature of the
goldfinch is in summer (for environmental temperatures varying from 22
to 26°C) appro 32°C and in winter (for environmental temperatures from
0-7 0c) appro 28.3 0C. This phenomenon, thoroughly examined in several
kinds of birds, depends directly on adaptation temperatures. The results on
heat production of the two species of birds, measured at the respective
neutral temperature, are given in Table 1. By comparing BMR of the birds,
obtained in July and in January, with earlier findings at different adaptation
temperatures during one season [4,5], it is seen, that a close correspondence
exists: in cold season, high BMR; in warm season, low BMR occurs (the
differences are statistically highly significant).
3. Heat Production at about + 1 °C
The problem of thermoregulation in different seasons is an age old one,
known since EDWARDS [3] hinted at the seasonal variation in the capability
of birds to produce heat. In confirming the early observations made by
EDwARDs, our results (Table 1) show that also at low experimental
temperature of about 1 °C birds have in winter a higher metabolism than in
summer.
Discussion
In the range of temperature allowing BMR in both warm and cold
seasons, the heat production of goldfinches is higher than that of canaries,
which could be interpreted as a condition for the wide distribution of the
goldfinches in Central Europe. However, the observed result also seems to
demonstrate that in goldfinches the morphological type of seasonal adaptation has not yet been achieved as a consequence of the improved insulation by pelt or plumage [8], this type of adaptation allows animals of the
northern regions to produce less heat at the same external temperatures
than animals of southern regions.
occurred at ambient temperature of 29.2 °C in winter and of 33.6 °C in
summer. In winter canaries at ambient temperature of 36.1 °C panting
occurs, whilest in summer canaries at 37°C. These results confirm earlier
observations on birds [4, 5].
2. Basal Metabolism
By analyzing BMR obtained at neutral temperatures, we find that BMR
appears in winter at 30°C environmental temperature, after a stay of appro
3-4 weeks at -6 to + 8 °C; in summer it occurs at 33°C, if the birds are
living at temperatures between 23 and 28 0C. The neutral temperature of the
goldfinch is in summer (for environmental temperatures varying from 22
to 26°C) appro 32°C and in winter (for environmental temperatures from
0-7 0c) appro 28.3 0C. This phenomenon, thoroughly examined in several
kinds of birds, depends directly on adaptation temperatures. The results on
heat production of the two species of birds, measured at the respective
neutral temperature, are given in Table 1. By comparing BMR of the birds,
obtained in July and in January, with earlier findings at different adaptation
temperatures during one season [4,5], it is seen, that a close correspondence
exists: in cold season, high BMR; in warm season, low BMR occurs (the
differences are statistically highly significant).
3. Heat Production at about + 1 °C
The problem of thermoregulation in different seasons is an age old one,
known since EDWARDS [3] hinted at the seasonal variation in the capability
of birds to produce heat. In confirming the early observations made by
EDwARDs, our results (Table 1) show that also at low experimental
temperature of about 1 °C birds have in winter a higher metabolism than in
summer.
Discussion
In the range of temperature allowing BMR in both warm and cold
seasons, the heat production of goldfinches is higher than that of canaries,
which could be interpreted as a condition for the wide distribution of the
goldfinches in Central Europe. However, the observed result also seems to
demonstrate that in goldfinches the morphological type of seasonal adaptation has not yet been achieved as a consequence of the improved insulation by pelt or plumage [8], this type of adaptation allows animals of the
northern regions to produce less heat at the same external temperatures
than animals of southern regions.