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
Background:Physiological preparation for reproduction in small passerines involves the increased secretion of reproductive hormones, elevation of the metabolic rate and energy storage, all of which are essential for r...Background:Physiological preparation for reproduction in small passerines involves the increased secretion of reproductive hormones, elevation of the metabolic rate and energy storage, all of which are essential for reproduction. However, it is unclear whether the timing of the physiological processes involved is the same in resident and migrant species that breed in the same area. To answer this question, we compared temporal variation in the plasma concentration of luteinizing hormone(LH), testosterone(T), estradiol(E_2), triiothyronine(T_3) and body mass, between a migrant species, the Eurasian Skylark(Alauda arvensis) and a resident species, the Asian Short-toed Lark(Calandrella cheleensis), both of which breed in northeastern Inner Mongolia, China, during the 2014 and 2015 breeding seasons.Methods:Twenty adult Eurasian Skylarks and twenty Asian Short-toed Larks were captured on March 15, 2014 and 2015 and housed in out-door aviaries. Plasma LH, T(males), E_2(females), T_3 and the body mass of each bird were measured every six days from March 25 to May 6.Results:With the exception of T, which peaked earlier in the Asian Short-toed Lark in 2014, plasma concentrations of LH, T, E_2 and T_3 of both species peaked at almost the same time. However, Asian Short-toed Larks attained peak body mass earlier than Eurasian Skylarks. Plasma T_3 concentrations peaked 12 days earlier than plasma LH in both species. Generally, plasma LH, T, E_2, T_3 and body mass, peaked earlier in both species in 2014 than 2015.Conclusions:The timing of pre-reproductive changes in the endocrine system and energy metabolism can be the same in migrant and resident species; however, residents may accumulate energy reserves faster than migrants. Although migration does not affect the timing of pre-breeding reproductive and metabolic changes, migrant species may need more time to increase their body mass. T levels in resident species may be accelerated by higher spring temperatures that may also advance the pre-breeding preparation of both migrants and residents.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.
基金supported by grants from the National Nature Science Foundation of China (No. 31372225)the Minzu University Research fund (ydzxxk201619, ydzxxk201618)111 Project (B08044)
文摘Background:Physiological preparation for reproduction in small passerines involves the increased secretion of reproductive hormones, elevation of the metabolic rate and energy storage, all of which are essential for reproduction. However, it is unclear whether the timing of the physiological processes involved is the same in resident and migrant species that breed in the same area. To answer this question, we compared temporal variation in the plasma concentration of luteinizing hormone(LH), testosterone(T), estradiol(E_2), triiothyronine(T_3) and body mass, between a migrant species, the Eurasian Skylark(Alauda arvensis) and a resident species, the Asian Short-toed Lark(Calandrella cheleensis), both of which breed in northeastern Inner Mongolia, China, during the 2014 and 2015 breeding seasons.Methods:Twenty adult Eurasian Skylarks and twenty Asian Short-toed Larks were captured on March 15, 2014 and 2015 and housed in out-door aviaries. Plasma LH, T(males), E_2(females), T_3 and the body mass of each bird were measured every six days from March 25 to May 6.Results:With the exception of T, which peaked earlier in the Asian Short-toed Lark in 2014, plasma concentrations of LH, T, E_2 and T_3 of both species peaked at almost the same time. However, Asian Short-toed Larks attained peak body mass earlier than Eurasian Skylarks. Plasma T_3 concentrations peaked 12 days earlier than plasma LH in both species. Generally, plasma LH, T, E_2, T_3 and body mass, peaked earlier in both species in 2014 than 2015.Conclusions:The timing of pre-reproductive changes in the endocrine system and energy metabolism can be the same in migrant and resident species; however, residents may accumulate energy reserves faster than migrants. Although migration does not affect the timing of pre-breeding reproductive and metabolic changes, migrant species may need more time to increase their body mass. T levels in resident species may be accelerated by higher spring temperatures that may also advance the pre-breeding preparation of both migrants and residents.
