The effect of nestboxes on the vernal increase and decrease in reproductive activity was investig... more The effect of nestboxes on the vernal increase and decrease in reproductive activity was investigated in male European starlings (Sturnus vulgaris), held in outdoor aviaries. Male-only groups with (group 1) and without (group 2) availability of nestboxes were compared for the amount of song, for testicular size and plasma titers of luteinizing hormone (LH) and testosterone. Testicular size and LH differed significantly between the 2 groups, being higher in males with nestboxes. Similar differences, as well as differences in nestbox-related behaviors (sitting in front of a nestbox, inspecting it, and nestbuilding) were also found when individuals of group 1, in possession of a nestbox, were compared to those without. In another group (2), the seasonal dependence of nestboxes as a modifying factor was investigated. These males were given access to nestboxes later in the season, than the males of group 1, after April 7. The effects on physiological parameters at this time of year were negligible in that only a transient increase in LH was seen compared to group 3. Nestbox-oriented behaviors did not reach the same intensities as in group 1. These results demonstrate the importance of nest-site availability in modifying behavioral and physiological functions during the vernal reproductive cycle. At the same time they indicate a seasonal dependence in these modifying effects.
Development of avian embryos requires thermal energy, usually from parents. Parents may, however,... more Development of avian embryos requires thermal energy, usually from parents. Parents may, however, trade off catering for embryonic requirements against their own need to forage through intermittent incubation. This dynamically adjusted behaviour can be affected by properties of the nest. Here, we experimentally show a novel mechanism by which parents, through incorporation of aromatic herbs into nests, effectively modify their incubation behaviour to the benefit of their offspring. Our study species, the European starling, includes in its nest aromatic herbs which promote offspring fitness. We provided wild starlings with artificial nests including or excluding the typically selected fresh herbs and found strong support for our prediction of facilitated incubation. Herb effects were not explained by thermal changes of the nests <i>per se</i>, but by modified parental behaviours. Egg temperatures and nest attendance were higher in herb than herbless nests, egg temperatures dropped less frequently below critical thresholds and parents started their active day earlier. These effects were dynamic over time and particularly strong during early incubation. Incubation period was shorter in herb nests, and nestlings were heavier one week after hatching. Aromatic herbs hence influenced incubation in beneficial ways for offspring, possibly through pharmacological effects on incubating parents.
Male European starlings (Sturnus vulgaris) use odorous herbs as green nest material. They show th... more Male European starlings (Sturnus vulgaris) use odorous herbs as green nest material. They show these plants to females to catch their attention before they incorporate them into their nests. Nestlings reared in nests containing herbs carry fewer bacteria, have higher haematocrit levels and more basophile leucocytes, and have a higher fledging weight than those reared in nests without herbs. The incubation temperature is higher in nests with herbs than in herbless nests. Females are attracted by herb nests and herb nests provide energy-saving benefits to incubating females. In choice experiments, starlings employed olfaction to select nest herbs, using innate information and experience acquired as nestlings to identify odours. Measures of head space air in starling nest boxes revealed an increase of volatile substances during the nestlings phase. Manganese-enhanced resonance imaging of the olfactory bulb of starling showed that the neural correlates of olfactory sensitivity change seasonally. Starlings can only discriminate odours during the reproductive season. The association between odour perception and reproductive behaviour suggests that increased testosterone production, related to the increasing photoperiod in spring, may guide these seasonal changes. The size of the olfactory bulb but not its ability to discriminate was affected by testosterone implants in the non-reproductive season.
European starlings add fresh green plants to their dry nest material. Male starlings of our 60-ne... more European starlings add fresh green plants to their dry nest material. Male starlings of our 60-nest-box colony carried 68 different plant species into their nests. Some males were polygynous and had 3-6 clutches, others were monogynous and had 1-2 clutches per reproductive season. The 'nest protection hypothesis' proposes that insecticidal compounds in green plants reduce the parasite load of the nests. The 'courtship hypothesis' predicts that carrying nest greenery is a courtship activity to attract females. The aim of this study was to collect field data suitable for distinguishing these two hypotheses. 1. Some plant species occurred more often in the nest-boxes than expected from their frequency in the nest-box environment. A significant number of these preferred plants were rich in volatiles, some of which are said to be insecticidal. But volatiles could also attract females and/or influence their breeding activity and the chicks' development directly. 2. The males carried greenery into their nest boxes maximal around 5 days before the onset of laying, when pair formation took place, and ceased this behaviour with egg deposition. The total amount of greenery deposited in a nest-box was a function of the number of days of courtship a male needed to attract a female. 3. Polygynous males deposited the same amount of greenery in their first nest as monogynous males. In additional nests polygynous males deposited more greenery. However, this was due to the fact that these additional nests were advertised for a longer time.
Single entry per nest containing overall information. For details see Publication and Supplements... more Single entry per nest containing overall information. For details see Publication and Supplements, and the ReadMe file
Development of avian embryos requires thermal energy, usually from parents. Parents may, however,... more Development of avian embryos requires thermal energy, usually from parents. Parents may, however, trade-off catering for embryonic requirements against their own need to forage through intermittent incubation. This dynamically adjusted behaviour can be affected by properties of the nest. Here, we experimentally show a novel mechanism by which parents, through incorporation of aromatic herbs into nests, effectively modify their incubation behaviour to the benefit of their offspring. Our study species, the European starling, includes in its nest aromatic herbs which promote offspring fitness. We provided wild starlings with artificial nests including or excluding the typically selected fresh herbs and found strong support for our prediction of facilitated incubation. Herb effects were not explained by thermal changes of the nests <i>per se</i>, but by modified parental behaviours. Egg temperatures and nest attendance were higher in herb than herbless nests, egg temperature...
Development of avian embryos requires thermal energy, usually from parents. Parents may, however,... more Development of avian embryos requires thermal energy, usually from parents. Parents may, however, trade-off catering for embryonic requirements against their own need to forage through intermittent incubation. This dynamically adjusted behaviour can be affected by properties of the nest. Here, we experimentally show a novel mechanism by which parents, through incorporation of aromatic herbs into nests, effectively modify their incubation behaviour to the benefit of their offspring. Our study species, the European starling, includes in its nest aromatic herbs which promote offspring fitness. We provided wild starlings with artificial nests including or excluding the typically selected fresh herbs and found strong support for our prediction of facilitated incubation. Herb effects were not explained by thermal changes of the nests <i>per se</i>, but by modified parental behaviours. Egg temperatures and nest attendance were higher in herb than herbless nests, egg temperature...
Development of avian embryos requires thermal energy, usually from parents. Parents may, however,... more Development of avian embryos requires thermal energy, usually from parents. Parents may, however, trade off catering for embryonic requirements against their own need to forage through intermittent incubation. This dynamically adjusted behaviour can be affected by properties of the nest. Here, we experimentally show a novel mechanism by which parents, through incorporation of aromatic herbs into nests, effectively modify their incubation behaviour to the benefit of their offspring. Our study species, the European starling, includes in its nest aromatic herbs which promote offspring fitness. We provided wild starlings with artificial nests including or excluding the typically selected fresh herbs and found strong support for our prediction of facilitated incubation. Herb effects were not explained by thermal changes of the nests <i>per se</i>, but by modified parental behaviours. Egg temperatures and nest attendance were higher in herb than herbless nests, egg temperatures dropped less frequently below critical thresholds and parents started their active day earlier. These effects were dynamic over time and particularly strong during early incubation. Incubation period was shorter in herb nests, and nestlings were heavier one week after hatching. Aromatic herbs hence influenced incubation in beneficial ways for offspring, possibly through pharmacological effects on incubating parents.
Development of avian embryos requires thermal energy, usually from parents. Parents may, however,... more Development of avian embryos requires thermal energy, usually from parents. Parents may, however, trade-off catering for embryonic requirements against their own need to forage through intermittent incubation. This dynamically adjusted behaviour can be affected by properties of the nest. Here, we experimentally show a novel mechanism by which parents, through incorporation of aromatic herbs into nests, effectively modify their incubation behaviour to the benefit of their offspring. Our study species, the European starling, includes in its nest aromatic herbs which promote offspring fitness. We provided wild starlings with artificial nests including or excluding the typically selected fresh herbs and found strong support for our prediction of facilitated incubation. Herb effects were not explained by thermal changes of the nests <i>per se</i>, but by modified parental behaviours. Egg temperatures and nest attendance were higher in herb than herbless nests, egg temperature...
European starlings add fresh green plants to their dry nest material. Male starlings of our 60-ne... more European starlings add fresh green plants to their dry nest material. Male starlings of our 60-nest-box colony carried 68 different plant species into their nests. Some males were polygynous and had 3-6 clutches, others were monogynous and had 1-2 clutches per reproductive season. The 'nest protection hypothesis' proposes that insecticidal compounds in green plants reduce the parasite load of the nests. The 'courtship hypothesis' predicts that carrying nest greenery is a courtship activity to attract females. The aim of this study was to collect field data suitable for distinguishing these two hypotheses. 1. Some plant species occurred more often in the nest-boxes than expected from their frequency in the nest-box environment. A significant number of these preferred plants were rich in volatiles, some of which are said to be insecticidal. But volatiles could also attract females and/or influence their breeding activity and the chicks' development directly. 2. The...
Development of avian embryos requires thermal energy, usually from parents. Parents may, however,... more Development of avian embryos requires thermal energy, usually from parents. Parents may, however, trade-off catering for embryonic requirements against their own need to forage through intermittent incubation. This dynamically adjusted behaviour can be affected by properties of the nest. Here, we experimentally show a novel mechanism by which parents, through incorporation of aromatic herbs into nests, effectively modify their incubation behaviour to the benefit of their offspring. Our study species, the European starling, includes in its nest aromatic herbs which promote offspring fitness. We provided wild starlings with artificial nests including or excluding the typically selected fresh herbs and found strong support for our prediction of facilitated incubation. Herb effects were not explained by thermal changes of the nests <i>per se</i>, but by modified parental behaviours. Egg temperatures and nest attendance were higher in herb than herbless nests, egg temperature...
The effect of nestboxes on the vernal increase and decrease in reproductive activity was investig... more The effect of nestboxes on the vernal increase and decrease in reproductive activity was investigated in male European starlings (Sturnus vulgaris), held in outdoor aviaries. Male-only groups with (group 1) and without (group 2) availability of nestboxes were compared for the amount of song, for testicular size and plasma titers of luteinizing hormone (LH) and testosterone. Testicular size and LH differed significantly between the 2 groups, being higher in males with nestboxes. Similar differences, as well as differences in nestbox-related behaviors (sitting in front of a nestbox, inspecting it, and nestbuilding) were also found when individuals of group 1, in possession of a nestbox, were compared to those without. In another group (2), the seasonal dependence of nestboxes as a modifying factor was investigated. These males were given access to nestboxes later in the season, than the males of group 1, after April 7. The effects on physiological parameters at this time of year were negligible in that only a transient increase in LH was seen compared to group 3. Nestbox-oriented behaviors did not reach the same intensities as in group 1. These results demonstrate the importance of nest-site availability in modifying behavioral and physiological functions during the vernal reproductive cycle. At the same time they indicate a seasonal dependence in these modifying effects.
Development of avian embryos requires thermal energy, usually from parents. Parents may, however,... more Development of avian embryos requires thermal energy, usually from parents. Parents may, however, trade off catering for embryonic requirements against their own need to forage through intermittent incubation. This dynamically adjusted behaviour can be affected by properties of the nest. Here, we experimentally show a novel mechanism by which parents, through incorporation of aromatic herbs into nests, effectively modify their incubation behaviour to the benefit of their offspring. Our study species, the European starling, includes in its nest aromatic herbs which promote offspring fitness. We provided wild starlings with artificial nests including or excluding the typically selected fresh herbs and found strong support for our prediction of facilitated incubation. Herb effects were not explained by thermal changes of the nests <i>per se</i>, but by modified parental behaviours. Egg temperatures and nest attendance were higher in herb than herbless nests, egg temperatures dropped less frequently below critical thresholds and parents started their active day earlier. These effects were dynamic over time and particularly strong during early incubation. Incubation period was shorter in herb nests, and nestlings were heavier one week after hatching. Aromatic herbs hence influenced incubation in beneficial ways for offspring, possibly through pharmacological effects on incubating parents.
Male European starlings (Sturnus vulgaris) use odorous herbs as green nest material. They show th... more Male European starlings (Sturnus vulgaris) use odorous herbs as green nest material. They show these plants to females to catch their attention before they incorporate them into their nests. Nestlings reared in nests containing herbs carry fewer bacteria, have higher haematocrit levels and more basophile leucocytes, and have a higher fledging weight than those reared in nests without herbs. The incubation temperature is higher in nests with herbs than in herbless nests. Females are attracted by herb nests and herb nests provide energy-saving benefits to incubating females. In choice experiments, starlings employed olfaction to select nest herbs, using innate information and experience acquired as nestlings to identify odours. Measures of head space air in starling nest boxes revealed an increase of volatile substances during the nestlings phase. Manganese-enhanced resonance imaging of the olfactory bulb of starling showed that the neural correlates of olfactory sensitivity change seasonally. Starlings can only discriminate odours during the reproductive season. The association between odour perception and reproductive behaviour suggests that increased testosterone production, related to the increasing photoperiod in spring, may guide these seasonal changes. The size of the olfactory bulb but not its ability to discriminate was affected by testosterone implants in the non-reproductive season.
European starlings add fresh green plants to their dry nest material. Male starlings of our 60-ne... more European starlings add fresh green plants to their dry nest material. Male starlings of our 60-nest-box colony carried 68 different plant species into their nests. Some males were polygynous and had 3-6 clutches, others were monogynous and had 1-2 clutches per reproductive season. The 'nest protection hypothesis' proposes that insecticidal compounds in green plants reduce the parasite load of the nests. The 'courtship hypothesis' predicts that carrying nest greenery is a courtship activity to attract females. The aim of this study was to collect field data suitable for distinguishing these two hypotheses. 1. Some plant species occurred more often in the nest-boxes than expected from their frequency in the nest-box environment. A significant number of these preferred plants were rich in volatiles, some of which are said to be insecticidal. But volatiles could also attract females and/or influence their breeding activity and the chicks' development directly. 2. The males carried greenery into their nest boxes maximal around 5 days before the onset of laying, when pair formation took place, and ceased this behaviour with egg deposition. The total amount of greenery deposited in a nest-box was a function of the number of days of courtship a male needed to attract a female. 3. Polygynous males deposited the same amount of greenery in their first nest as monogynous males. In additional nests polygynous males deposited more greenery. However, this was due to the fact that these additional nests were advertised for a longer time.
Single entry per nest containing overall information. For details see Publication and Supplements... more Single entry per nest containing overall information. For details see Publication and Supplements, and the ReadMe file
Development of avian embryos requires thermal energy, usually from parents. Parents may, however,... more Development of avian embryos requires thermal energy, usually from parents. Parents may, however, trade-off catering for embryonic requirements against their own need to forage through intermittent incubation. This dynamically adjusted behaviour can be affected by properties of the nest. Here, we experimentally show a novel mechanism by which parents, through incorporation of aromatic herbs into nests, effectively modify their incubation behaviour to the benefit of their offspring. Our study species, the European starling, includes in its nest aromatic herbs which promote offspring fitness. We provided wild starlings with artificial nests including or excluding the typically selected fresh herbs and found strong support for our prediction of facilitated incubation. Herb effects were not explained by thermal changes of the nests <i>per se</i>, but by modified parental behaviours. Egg temperatures and nest attendance were higher in herb than herbless nests, egg temperature...
Development of avian embryos requires thermal energy, usually from parents. Parents may, however,... more Development of avian embryos requires thermal energy, usually from parents. Parents may, however, trade-off catering for embryonic requirements against their own need to forage through intermittent incubation. This dynamically adjusted behaviour can be affected by properties of the nest. Here, we experimentally show a novel mechanism by which parents, through incorporation of aromatic herbs into nests, effectively modify their incubation behaviour to the benefit of their offspring. Our study species, the European starling, includes in its nest aromatic herbs which promote offspring fitness. We provided wild starlings with artificial nests including or excluding the typically selected fresh herbs and found strong support for our prediction of facilitated incubation. Herb effects were not explained by thermal changes of the nests <i>per se</i>, but by modified parental behaviours. Egg temperatures and nest attendance were higher in herb than herbless nests, egg temperature...
Development of avian embryos requires thermal energy, usually from parents. Parents may, however,... more Development of avian embryos requires thermal energy, usually from parents. Parents may, however, trade off catering for embryonic requirements against their own need to forage through intermittent incubation. This dynamically adjusted behaviour can be affected by properties of the nest. Here, we experimentally show a novel mechanism by which parents, through incorporation of aromatic herbs into nests, effectively modify their incubation behaviour to the benefit of their offspring. Our study species, the European starling, includes in its nest aromatic herbs which promote offspring fitness. We provided wild starlings with artificial nests including or excluding the typically selected fresh herbs and found strong support for our prediction of facilitated incubation. Herb effects were not explained by thermal changes of the nests <i>per se</i>, but by modified parental behaviours. Egg temperatures and nest attendance were higher in herb than herbless nests, egg temperatures dropped less frequently below critical thresholds and parents started their active day earlier. These effects were dynamic over time and particularly strong during early incubation. Incubation period was shorter in herb nests, and nestlings were heavier one week after hatching. Aromatic herbs hence influenced incubation in beneficial ways for offspring, possibly through pharmacological effects on incubating parents.
Development of avian embryos requires thermal energy, usually from parents. Parents may, however,... more Development of avian embryos requires thermal energy, usually from parents. Parents may, however, trade-off catering for embryonic requirements against their own need to forage through intermittent incubation. This dynamically adjusted behaviour can be affected by properties of the nest. Here, we experimentally show a novel mechanism by which parents, through incorporation of aromatic herbs into nests, effectively modify their incubation behaviour to the benefit of their offspring. Our study species, the European starling, includes in its nest aromatic herbs which promote offspring fitness. We provided wild starlings with artificial nests including or excluding the typically selected fresh herbs and found strong support for our prediction of facilitated incubation. Herb effects were not explained by thermal changes of the nests <i>per se</i>, but by modified parental behaviours. Egg temperatures and nest attendance were higher in herb than herbless nests, egg temperature...
European starlings add fresh green plants to their dry nest material. Male starlings of our 60-ne... more European starlings add fresh green plants to their dry nest material. Male starlings of our 60-nest-box colony carried 68 different plant species into their nests. Some males were polygynous and had 3-6 clutches, others were monogynous and had 1-2 clutches per reproductive season. The 'nest protection hypothesis' proposes that insecticidal compounds in green plants reduce the parasite load of the nests. The 'courtship hypothesis' predicts that carrying nest greenery is a courtship activity to attract females. The aim of this study was to collect field data suitable for distinguishing these two hypotheses. 1. Some plant species occurred more often in the nest-boxes than expected from their frequency in the nest-box environment. A significant number of these preferred plants were rich in volatiles, some of which are said to be insecticidal. But volatiles could also attract females and/or influence their breeding activity and the chicks' development directly. 2. The...
Development of avian embryos requires thermal energy, usually from parents. Parents may, however,... more Development of avian embryos requires thermal energy, usually from parents. Parents may, however, trade-off catering for embryonic requirements against their own need to forage through intermittent incubation. This dynamically adjusted behaviour can be affected by properties of the nest. Here, we experimentally show a novel mechanism by which parents, through incorporation of aromatic herbs into nests, effectively modify their incubation behaviour to the benefit of their offspring. Our study species, the European starling, includes in its nest aromatic herbs which promote offspring fitness. We provided wild starlings with artificial nests including or excluding the typically selected fresh herbs and found strong support for our prediction of facilitated incubation. Herb effects were not explained by thermal changes of the nests <i>per se</i>, but by modified parental behaviours. Egg temperatures and nest attendance were higher in herb than herbless nests, egg temperature...
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