The incubating behavior of the horned lark and small skylark was studied in alpine meadows. The key results are: ① There was no significant difference in the temperature outside the nests of horned larks and small sk...The incubating behavior of the horned lark and small skylark was studied in alpine meadows. The key results are: ① There was no significant difference in the temperature outside the nests of horned larks and small skylarks ( F 1, 87 =3 286,P >0 05). ② If parents were off the nest, the temperature in the nest was not significantly different between the two species( F 1,87 =3 009,P >0 05), however, if parent birds were on the nest, the temperature in horned lark nests was significantly higher than that in small lark nests ( F 1, 210 =7 555,P <0 01). ③ Temperature trends inside and outside the nests of the two species were similar, both following a low high low, pattern and showed a significantly positive correlation(horned lark: r=0 572, n=158, P <0 01;small skylark: r=0 511, n=141, P <0 01). ④ During the hatching period, the temperature in nests was significantly higher than the outside temperature in horned larks( t=7 051, df=157, P <0 01), however, there was no significant difference between the inside and outside in the small skylark( t=-1 558, df=149, P >0 05). ⑤ The attendance time of horned larks and small skylarks showed three peaks; before 09:00 h, between 12:00 and 15:00 and after 19:00 h, respectively. ⑥ The attendance time and incubation behavior of the two species changed with variation in the environmental temperature. ⑦ There was no significant difference in the average attendance time per day between horned larks and small skylarks( P >0 05). ⑧ The attendance frequency of horned larks was high (4 17 times/h), and visit duration short (524 32 s/period), wherase small larks showed the opposite pattern; low attendance frequency(1 79 times/h)with relatively long( 1 510 00 s/ periods)visits. Our results are consistent with the hypothesis that attendance time is a balance between the energy requirements of the parent birds and the temperature requirements of the developing embryos. It follows that a birds choice of nest site should involve a trade off between costs and benefits, e.g. microclimate versus proximity to food resources.展开更多
文摘The incubating behavior of the horned lark and small skylark was studied in alpine meadows. The key results are: ① There was no significant difference in the temperature outside the nests of horned larks and small skylarks ( F 1, 87 =3 286,P >0 05). ② If parents were off the nest, the temperature in the nest was not significantly different between the two species( F 1,87 =3 009,P >0 05), however, if parent birds were on the nest, the temperature in horned lark nests was significantly higher than that in small lark nests ( F 1, 210 =7 555,P <0 01). ③ Temperature trends inside and outside the nests of the two species were similar, both following a low high low, pattern and showed a significantly positive correlation(horned lark: r=0 572, n=158, P <0 01;small skylark: r=0 511, n=141, P <0 01). ④ During the hatching period, the temperature in nests was significantly higher than the outside temperature in horned larks( t=7 051, df=157, P <0 01), however, there was no significant difference between the inside and outside in the small skylark( t=-1 558, df=149, P >0 05). ⑤ The attendance time of horned larks and small skylarks showed three peaks; before 09:00 h, between 12:00 and 15:00 and after 19:00 h, respectively. ⑥ The attendance time and incubation behavior of the two species changed with variation in the environmental temperature. ⑦ There was no significant difference in the average attendance time per day between horned larks and small skylarks( P >0 05). ⑧ The attendance frequency of horned larks was high (4 17 times/h), and visit duration short (524 32 s/period), wherase small larks showed the opposite pattern; low attendance frequency(1 79 times/h)with relatively long( 1 510 00 s/ periods)visits. Our results are consistent with the hypothesis that attendance time is a balance between the energy requirements of the parent birds and the temperature requirements of the developing embryos. It follows that a birds choice of nest site should involve a trade off between costs and benefits, e.g. microclimate versus proximity to food resources.
