Nest-site selection patterns of Red-crowned cranes(Grus japonensis) and the effects of environmental variables were studied during the years of 2002-2008 in Zhalong Nature Reserve,Qiqihar city,northeast China.The ne...Nest-site selection patterns of Red-crowned cranes(Grus japonensis) and the effects of environmental variables were studied during the years of 2002-2008 in Zhalong Nature Reserve,Qiqihar city,northeast China.The nest-site selection pattern of Red-crowned cranes included two orders and three choices:the choice of nest-site habitat type within the macro-habitat order,nest zone selection and nest-site micro-habitat selection within the micro-habitat order.Various habitats(such as Carex swamps and reed fire districts) can be selected as the nest sites for Red-crowned cranes,of which reed swamps(93.15%) are given a preference.Factor Analysis reveals that the micro-habitat selection are affected by four main factors:fire,security(concealment /disturbance),incubation(conditions,nest-material),and food.Further analysis reveals that Red-crowned cranes have certain adaptability to the changes of nesting habitat quality in the Zhalong wetlands.In conclusion,fire,reeds,and water were the most important variables for nest-site habitat selection of Red-crowned Cranes in Zhalong Nature Reserve.展开更多
Background: The Emei Shan Liocichla(Liocichla omeiensis) is a globally vulnerable babbler, endemic to southwestern China. We investigated its nest predators, nest-site selection and nest success at the Laojunshan Nati...Background: The Emei Shan Liocichla(Liocichla omeiensis) is a globally vulnerable babbler, endemic to southwestern China. We investigated its nest predators, nest-site selection and nest success at the Laojunshan National Nature Reserve in Sichuan, China in order to identify the precise nesting-habitat requirements of the species, and to test whether the nest-site-selection cues, preferred by the Emei Shan Liocichla, are positively associated with nest success.Methods: We used infrared cameras to determine nest predators. We compared the microhabitat attributes between nest and random sites, as well as successful and failed nests. We used Binary Logistic Regression to determine the most important variables affecting nest-site selection of the Emei Shan Liocichla. We used the nest survival analysis in Program MARK to estimate daily nest survival rates(DSR). Nest success was calculated using the Mayfield method.Results: In total 56 nests were found. The DSR for all nests that contained at least one egg was 0.9564 ± 0.0091(95 % CI 0.9346–0.9711)(n = 40), while the total nest success was 27.5 %. We identified four categories of predators in 10 nest predation events, i.e. squirrels(n = 5), snakes(n = 3), raptors(n = 1) and wasps(n = 1). We found that:(1) nest predation was the primary reason for nest failure of the Emei Shan Liocichla,(2) tree cover, bamboo cover, liana abundance and distance to forest edge or gap were the most important variables affecting nest-site selection of this species, and(3) the nest-site-selection variables we measured appeared not to be positively associated with nest success.Conclusions: Our findings suggest that the Emei Shan Liocichla tended to select nest sites near forest edges or gaps with good concealment and that nest-site selection by this species was nonrandom but not necessarily adaptive. Reducing forest-edge development and protecting bamboo stands should be effective for conservation of this species.展开更多
Background:Floods and other extreme events have disastrous effects on wetland breeding birds.However,such events and their consequences are difficult to study due to their rarity and unpredictable occurrence.Methods:H...Background:Floods and other extreme events have disastrous effects on wetland breeding birds.However,such events and their consequences are difficult to study due to their rarity and unpredictable occurrence.Methods:Here we compared nest-sites chosen by Reed Parrotbills(Paradoxornis heudei) during June-August 2016 in Yongnianwa Wetlands,Hebei Province,China,before and after an extreme flooding event.Results:Twenty-three nests were identified before and 13 new nests after the flood.There was no significant difference in most nest-site characteristics,such as distance from the road,height of the reeds in which nests were built,or nest volume before or after the flood.However,nests after the flood were located significantly higher in the vegetation compared to before the flood(mean ± SE:1.17 ± 0.13 m vs.0.75 ± 0.26 m,p < 0.01).However,predation rate also increased significantly after the flood(67% vs.25%,p = 0.030).Conclusions:Our results suggested that Reed Parrotbills demonstrated behavioral plasticity in their nest-site selection.Thus,they appeared to increase the height of their nests in response to the drastically changing water levels in reed wetlands,to reduce the likelihood that their nests would be submerged again by flooding.However,predation rate also increased significantly after the flood,suggesting that the change in nest height to combat the threat of flooding made the nests more susceptible to other threats,such as predation.Animals' response to rare climatic events,such as flooding,may produce ecological traps if they make the animals more susceptible to other kinds of threats they are more likely to continue to encounter.展开更多
Background:Information pertaining to nest-site fidelity and breeding dispersal over successive years can help to better our understanding of how birds respond to nest predation.Methods:By using mist nets and tracking ...Background:Information pertaining to nest-site fidelity and breeding dispersal over successive years can help to better our understanding of how birds respond to nest predation.Methods:By using mist nets and tracking the color banded individuals,we investigated nest-site fidelity and breeding dispersal by Common Tailorbirds(Orthotomus sutorius)throughout a year and between successive years in 2017–2018.Results:The present study showed that Common Tailorbirds could produce up to four clutches per breeding season.When multiple broods were produced within a year,breeding pairs remained together,and the nest rebuilding rate was up to 92.2%,with only four cases(7.8%)in which birds reused their old nests.The dispersal distance between the nests during multiple breeding was found to be 10.0±10.5 m,and nest-site fidelity within the same year was 90.0%.By the second year of breeding,76.2%of individuals remained in the original breeding pairs,while for those that did switch partners,the females remained in the nest from the previous year and paired with new males.The dispersal distance between years was 26.5±41.9 m,and nest-site fidelity between different years was 80.1%.There was no significant difference between within-year and between-year dispersal distances.Moreover,there was no significant difference in the dispersal distance of rebuilt nests between birds that had experienced nest predation and those that had not.Conclusions:Our findings suggest that Common Tailorbirds maintain a high degree of fidelity to mates and nestsites,and nest predation had no significant effect on territorial changes or breeding dispersal distance between each breeding attempt.展开更多
Providing nest-boxes as surrogate tree cavities can be of great importance to increase the breeding populations of cavity-nesting birds in managed forests.However,the exact placement of nest-boxes should be taken into...Providing nest-boxes as surrogate tree cavities can be of great importance to increase the breeding populations of cavity-nesting birds in managed forests.However,the exact placement of nest-boxes should be taken into consideration to enhance their occupancy according to species-specific preferences.In this study,we investigated which factors can better predict nest-box occupancy by the Great Tit(Parus major)in eucalypt plantations.We used generalised linear mixed-effects models to analyse the influence of topography,nest-box positioning,vegetation cover and landscape variables on three-year occupancy records from 80 newly provided nest-boxes.Non-random patterns of nest-box occupancy were found with respect to all categories except topography.Results suggest that Great Tits prefer to occupy high-placed nest-boxes,close to areas that can provide them with supplementary resources either within or in the vicinity of the stand(i.e.,trees other than eucalypts,riparian vegetation,and large patches of adjacent habitats).Overall,this study provides important recommendations for nest-box placement and spatial distribution in managed forests and enhances the potential of nest-box interventions as a biodiversity offset and management tool.展开更多
The quality of a breeding site may have major fitness consequences.A fundamental step to understanding the process of nest-site selection is the identification of the information individuals use to choose high-quality...The quality of a breeding site may have major fitness consequences.A fundamental step to understanding the process of nest-site selection is the identification of the information individuals use to choose high-quality nest sites.For secondary cavity-nesting bird species that do not add nest lining material,organic remains (faeces,pellets)accumulated inside nest cavities during previous breeding events may be a cue for high-quality nest-sites,as they contain information about past successful breeding and may improve thermal insulation of eggs during incubation.However,cavities in which breeding was successful might also contain more nest-dwelling ectoparasites than unoccupied cavities, offering an incentive for prospective parents to avoid them.We exposed breeding cavity-nesting lesser kestrels (Falco naumanni)to nestbox dyads consisting of a dirty (with a thick layer of organic substrate) and a clean nestbox (without organic material).Dirty nestboxes were strongly preferred,being occupied earlier and more frequently than clean ones.Hatching success in dirty nestboxes was significantly higher than in clean ones,suggesting a positive effect of organic nest material on incubation efficiency, while nestbox dirtiness did not significantly affect clutch and brood size.Nestlings from dirty nestboxes had significantly higher ectoparasite load than those from clean nestboxes soon after egg hatching,but this difference was not evident a few days later.Nest substrate did not significantly affect nestling growth.We concluded that nest substrate is a key driver of nest-site choice in lesser kestrels,although the adaptive value of such a strong preference appears elusive and may be context-dependent.展开更多
Little is known about the ecology of the Chinese Giant Salamander(Andrias davidianus), a critically endangered species. Such information is needed to make informed decisions concerning the conservation and management ...Little is known about the ecology of the Chinese Giant Salamander(Andrias davidianus), a critically endangered species. Such information is needed to make informed decisions concerning the conservation and management of this species. Four A. davidianus raised in a pool were released into their native habitat on 04 May 2005 and were subsequently radio-tracked for approximately 155–168 days. Following their release, the giant salamanders traveled upstream in search of suitable micro-habitats, and settled after 10 days. Later, a devastating summer flash flood destroyed the salamanders' dens, triggering another bout of habitat searching by the animals. Eventually, the salamanders settled in different sections of the stream where they remained until the end of the study. On average, each habitat searching endeavor took 7.5 days, during which a giant salamander explored a 310 m stretch of stream with a surface area of about 1157 m2 and occupied 3.5 temporary dwellings. Each giant salamander spent an average of 144.5 days in semi-permanent micro-habitats, and occupied territories that had a mean size of 34.75 m2. Our results indicate that the Chinese giant salamander responds to habitat disturbance by seeking new habitats upstream, both water temperature and water level affect the salamander's habitat searching activity, and the size of the salamander's semi-permanent territory is influenced by the size of the pool containing the animal's den.展开更多
From April to July 2003 and 2004,we surveyed the nest-site selection of the White Eared pheasant(Crossoptilon crossoptilon)in the Zhujie Monastery and in the mountain facing it in Sichuan Province,China.In this paper,...From April to July 2003 and 2004,we surveyed the nest-site selection of the White Eared pheasant(Crossoptilon crossoptilon)in the Zhujie Monastery and in the mountain facing it in Sichuan Province,China.In this paper,we studied the nest characteristics and the clutch size of the pheasant.Habitat sampling method was used to determine the variables that might affect the nest-site selection of the White Eared pheasant.Chi-square test was used to identify which habitat type was likely to be preferred by the bird.Independent-samples t test and Mann–Whitney U test were used to find which variables were important for the birds’nest-site selection.A total of 13 nests were found.Oak shrub was greatly preferred as nest sites(84.62%).Nests under a rock wall(7.69%)and a fallen tree(7.69%)were also found.The average clutch size of a White Eared pheasant is 7.33±0.54(range,5–11;n=12).Laying period was between April 27 and May 21.In the Zhujie area,1 nest was in the forest and 11 nests were in oak shrubs.The species preferred oak shrub as its nesting habitat(χ^(2)=8.333,df=1,P<0.05).The bird was more likely to place its nest in sites with a high coverage,i.e.0.5,1,and 2 m above the ground(independent-samples t test,P<0.05),and with a large shrub diameter(Mann–Whitney U test,P<0.05).The species are more likely to prefer sites with plant cover,shrub cover(independentsamples t test,P<0.05),and shrub height(Mann–Whitney U test,P<0.05)in a relatively small range.展开更多
Vertebrate embryos require access to water;however,many species nest in terrestrial habitats that vary considerably in moisture content.Oviparous,non-avian reptiles have served as models to understand how environmenta...Vertebrate embryos require access to water;however,many species nest in terrestrial habitats that vary considerably in moisture content.Oviparous,non-avian reptiles have served as models to understand how environmental factors,like moisture availability,influence development because eggs are often exposed to prevailing environments in the absence of parental care.Though much research demonstrates the importance of water absorption by eggs,many ecological factors that influence moisture availability in natural nests have received little attention.For example,the type of substrate in which nests are constructed is understudied.We experimentally incubated eggs of the brown anole lizard(Anolis sagrei)in 2 naturally occurring nest substrates that were treated with varying amounts of water to determine how natural substrates influence development at different moisture concentrations.One substrate consisted of sand and crushed seashells and the other was mostly organic material(i.e.decayed plant material).Both are common nesting substrates at our field site.When controlling for water uptake by eggs,we found that egg survival and hatchling phenotypes were similar between substrates;however,embryos developed more quickly in the sand/shell substrate than the organic substrate,indicating substrate-specific effects on embryo physiology.These results demonstrate that different natural substrates can result in similar developmental outcomes if the water available to eggs is comparable;however,some aspects of development,like developmental rate,are affected by the type of substrate,independent of water availability.Further study is required to determine how natural substrates influence embryo physiology independent of water content.展开更多
基金supported by the 11th Five-Year National Science and Technology plans to support key project (No. 2008BADB0B01)the Program for New Century Excellent Talents in Universities, the National Natural Science Foundation of China (No. 30670350 and 31070345)
文摘Nest-site selection patterns of Red-crowned cranes(Grus japonensis) and the effects of environmental variables were studied during the years of 2002-2008 in Zhalong Nature Reserve,Qiqihar city,northeast China.The nest-site selection pattern of Red-crowned cranes included two orders and three choices:the choice of nest-site habitat type within the macro-habitat order,nest zone selection and nest-site micro-habitat selection within the micro-habitat order.Various habitats(such as Carex swamps and reed fire districts) can be selected as the nest sites for Red-crowned cranes,of which reed swamps(93.15%) are given a preference.Factor Analysis reveals that the micro-habitat selection are affected by four main factors:fire,security(concealment /disturbance),incubation(conditions,nest-material),and food.Further analysis reveals that Red-crowned cranes have certain adaptability to the changes of nesting habitat quality in the Zhalong wetlands.In conclusion,fire,reeds,and water were the most important variables for nest-site habitat selection of Red-crowned Cranes in Zhalong Nature Reserve.
基金supported by the National Natural Science Foundation of China(No.31272330)the Scientific Research Innovation Team Projects of Leshan Normal University
文摘Background: The Emei Shan Liocichla(Liocichla omeiensis) is a globally vulnerable babbler, endemic to southwestern China. We investigated its nest predators, nest-site selection and nest success at the Laojunshan National Nature Reserve in Sichuan, China in order to identify the precise nesting-habitat requirements of the species, and to test whether the nest-site-selection cues, preferred by the Emei Shan Liocichla, are positively associated with nest success.Methods: We used infrared cameras to determine nest predators. We compared the microhabitat attributes between nest and random sites, as well as successful and failed nests. We used Binary Logistic Regression to determine the most important variables affecting nest-site selection of the Emei Shan Liocichla. We used the nest survival analysis in Program MARK to estimate daily nest survival rates(DSR). Nest success was calculated using the Mayfield method.Results: In total 56 nests were found. The DSR for all nests that contained at least one egg was 0.9564 ± 0.0091(95 % CI 0.9346–0.9711)(n = 40), while the total nest success was 27.5 %. We identified four categories of predators in 10 nest predation events, i.e. squirrels(n = 5), snakes(n = 3), raptors(n = 1) and wasps(n = 1). We found that:(1) nest predation was the primary reason for nest failure of the Emei Shan Liocichla,(2) tree cover, bamboo cover, liana abundance and distance to forest edge or gap were the most important variables affecting nest-site selection of this species, and(3) the nest-site-selection variables we measured appeared not to be positively associated with nest success.Conclusions: Our findings suggest that the Emei Shan Liocichla tended to select nest sites near forest edges or gaps with good concealment and that nest-site selection by this species was nonrandom but not necessarily adaptive. Reducing forest-edge development and protecting bamboo stands should be effective for conservation of this species.
基金supported by the National Natural Science Foundation of China(Nos.31672303 to CY,31472013 and 31772453 to WL)
文摘Background:Floods and other extreme events have disastrous effects on wetland breeding birds.However,such events and their consequences are difficult to study due to their rarity and unpredictable occurrence.Methods:Here we compared nest-sites chosen by Reed Parrotbills(Paradoxornis heudei) during June-August 2016 in Yongnianwa Wetlands,Hebei Province,China,before and after an extreme flooding event.Results:Twenty-three nests were identified before and 13 new nests after the flood.There was no significant difference in most nest-site characteristics,such as distance from the road,height of the reeds in which nests were built,or nest volume before or after the flood.However,nests after the flood were located significantly higher in the vegetation compared to before the flood(mean ± SE:1.17 ± 0.13 m vs.0.75 ± 0.26 m,p < 0.01).However,predation rate also increased significantly after the flood(67% vs.25%,p = 0.030).Conclusions:Our results suggested that Reed Parrotbills demonstrated behavioral plasticity in their nest-site selection.Thus,they appeared to increase the height of their nests in response to the drastically changing water levels in reed wetlands,to reduce the likelihood that their nests would be submerged again by flooding.However,predation rate also increased significantly after the flood,suggesting that the change in nest height to combat the threat of flooding made the nests more susceptible to other threats,such as predation.Animals' response to rare climatic events,such as flooding,may produce ecological traps if they make the animals more susceptible to other kinds of threats they are more likely to continue to encounter.
基金funded by the National Natural Science Foundation of China(Nos.31472013 and 31772453 to WL)
文摘Background:Information pertaining to nest-site fidelity and breeding dispersal over successive years can help to better our understanding of how birds respond to nest predation.Methods:By using mist nets and tracking the color banded individuals,we investigated nest-site fidelity and breeding dispersal by Common Tailorbirds(Orthotomus sutorius)throughout a year and between successive years in 2017–2018.Results:The present study showed that Common Tailorbirds could produce up to four clutches per breeding season.When multiple broods were produced within a year,breeding pairs remained together,and the nest rebuilding rate was up to 92.2%,with only four cases(7.8%)in which birds reused their old nests.The dispersal distance between the nests during multiple breeding was found to be 10.0±10.5 m,and nest-site fidelity within the same year was 90.0%.By the second year of breeding,76.2%of individuals remained in the original breeding pairs,while for those that did switch partners,the females remained in the nest from the previous year and paired with new males.The dispersal distance between years was 26.5±41.9 m,and nest-site fidelity between different years was 80.1%.There was no significant difference between within-year and between-year dispersal distances.Moreover,there was no significant difference in the dispersal distance of rebuilt nests between birds that had experienced nest predation and those that had not.Conclusions:Our findings suggest that Common Tailorbirds maintain a high degree of fidelity to mates and nestsites,and nest predation had no significant effect on territorial changes or breeding dispersal distance between each breeding attempt.
基金co-financed by Funda?ao para a Ciencia e a Tecnologia(FCT)the European Regional Development Fund(FEDER)through Portugal 2020 Competitiveness and Internationalization Operational Programme(POCI),reference POCI-01-0145-FEDER-030250 and PTDC/ASP-SIL/30250/2017-TOPDEVIL+1 种基金the R&D Unit Centre for Functional Ecology-Science for People and the Planet(CFE),with reference UIDB/04004/2020,financed by FCT/MCTES through national funds(PIDDAC)FCT/MCTES also funded L.P.S.with contract CEECIND/02064/2017。
文摘Providing nest-boxes as surrogate tree cavities can be of great importance to increase the breeding populations of cavity-nesting birds in managed forests.However,the exact placement of nest-boxes should be taken into consideration to enhance their occupancy according to species-specific preferences.In this study,we investigated which factors can better predict nest-box occupancy by the Great Tit(Parus major)in eucalypt plantations.We used generalised linear mixed-effects models to analyse the influence of topography,nest-box positioning,vegetation cover and landscape variables on three-year occupancy records from 80 newly provided nest-boxes.Non-random patterns of nest-box occupancy were found with respect to all categories except topography.Results suggest that Great Tits prefer to occupy high-placed nest-boxes,close to areas that can provide them with supplementary resources either within or in the vicinity of the stand(i.e.,trees other than eucalypts,riparian vegetation,and large patches of adjacent habitats).Overall,this study provides important recommendations for nest-box placement and spatial distribution in managed forests and enhances the potential of nest-box interventions as a biodiversity offset and management tool.
文摘The quality of a breeding site may have major fitness consequences.A fundamental step to understanding the process of nest-site selection is the identification of the information individuals use to choose high-quality nest sites.For secondary cavity-nesting bird species that do not add nest lining material,organic remains (faeces,pellets)accumulated inside nest cavities during previous breeding events may be a cue for high-quality nest-sites,as they contain information about past successful breeding and may improve thermal insulation of eggs during incubation.However,cavities in which breeding was successful might also contain more nest-dwelling ectoparasites than unoccupied cavities, offering an incentive for prospective parents to avoid them.We exposed breeding cavity-nesting lesser kestrels (Falco naumanni)to nestbox dyads consisting of a dirty (with a thick layer of organic substrate) and a clean nestbox (without organic material).Dirty nestboxes were strongly preferred,being occupied earlier and more frequently than clean ones.Hatching success in dirty nestboxes was significantly higher than in clean ones,suggesting a positive effect of organic nest material on incubation efficiency, while nestbox dirtiness did not significantly affect clutch and brood size.Nestlings from dirty nestboxes had significantly higher ectoparasite load than those from clean nestboxes soon after egg hatching,but this difference was not evident a few days later.Nest substrate did not significantly affect nestling growth.We concluded that nest substrate is a key driver of nest-site choice in lesser kestrels,although the adaptive value of such a strong preference appears elusive and may be context-dependent.
基金funded by the National Natural Science Foundation of China
文摘Little is known about the ecology of the Chinese Giant Salamander(Andrias davidianus), a critically endangered species. Such information is needed to make informed decisions concerning the conservation and management of this species. Four A. davidianus raised in a pool were released into their native habitat on 04 May 2005 and were subsequently radio-tracked for approximately 155–168 days. Following their release, the giant salamanders traveled upstream in search of suitable micro-habitats, and settled after 10 days. Later, a devastating summer flash flood destroyed the salamanders' dens, triggering another bout of habitat searching by the animals. Eventually, the salamanders settled in different sections of the stream where they remained until the end of the study. On average, each habitat searching endeavor took 7.5 days, during which a giant salamander explored a 310 m stretch of stream with a surface area of about 1157 m2 and occupied 3.5 temporary dwellings. Each giant salamander spent an average of 144.5 days in semi-permanent micro-habitats, and occupied territories that had a mean size of 34.75 m2. Our results indicate that the Chinese giant salamander responds to habitat disturbance by seeking new habitats upstream, both water temperature and water level affect the salamander's habitat searching activity, and the size of the salamander's semi-permanent territory is influenced by the size of the pool containing the animal's den.
基金supported by the National Sciences Foundation of China (no.30330050)the Chicago Zoological Society.
文摘From April to July 2003 and 2004,we surveyed the nest-site selection of the White Eared pheasant(Crossoptilon crossoptilon)in the Zhujie Monastery and in the mountain facing it in Sichuan Province,China.In this paper,we studied the nest characteristics and the clutch size of the pheasant.Habitat sampling method was used to determine the variables that might affect the nest-site selection of the White Eared pheasant.Chi-square test was used to identify which habitat type was likely to be preferred by the bird.Independent-samples t test and Mann–Whitney U test were used to find which variables were important for the birds’nest-site selection.A total of 13 nests were found.Oak shrub was greatly preferred as nest sites(84.62%).Nests under a rock wall(7.69%)and a fallen tree(7.69%)were also found.The average clutch size of a White Eared pheasant is 7.33±0.54(range,5–11;n=12).Laying period was between April 27 and May 21.In the Zhujie area,1 nest was in the forest and 11 nests were in oak shrubs.The species preferred oak shrub as its nesting habitat(χ^(2)=8.333,df=1,P<0.05).The bird was more likely to place its nest in sites with a high coverage,i.e.0.5,1,and 2 m above the ground(independent-samples t test,P<0.05),and with a large shrub diameter(Mann–Whitney U test,P<0.05).The species are more likely to prefer sites with plant cover,shrub cover(independentsamples t test,P<0.05),and shrub height(Mann–Whitney U test,P<0.05)in a relatively small range.
基金The research was approved by Auburn University IACUC(protocol 2019-3465)This study was supported by funds from Auburn University.J.M.H.was supported by the National Science Foundation(NSF DEB-1942145 to DAW)during the preparation of this manuscript.
文摘Vertebrate embryos require access to water;however,many species nest in terrestrial habitats that vary considerably in moisture content.Oviparous,non-avian reptiles have served as models to understand how environmental factors,like moisture availability,influence development because eggs are often exposed to prevailing environments in the absence of parental care.Though much research demonstrates the importance of water absorption by eggs,many ecological factors that influence moisture availability in natural nests have received little attention.For example,the type of substrate in which nests are constructed is understudied.We experimentally incubated eggs of the brown anole lizard(Anolis sagrei)in 2 naturally occurring nest substrates that were treated with varying amounts of water to determine how natural substrates influence development at different moisture concentrations.One substrate consisted of sand and crushed seashells and the other was mostly organic material(i.e.decayed plant material).Both are common nesting substrates at our field site.When controlling for water uptake by eggs,we found that egg survival and hatchling phenotypes were similar between substrates;however,embryos developed more quickly in the sand/shell substrate than the organic substrate,indicating substrate-specific effects on embryo physiology.These results demonstrate that different natural substrates can result in similar developmental outcomes if the water available to eggs is comparable;however,some aspects of development,like developmental rate,are affected by the type of substrate,independent of water availability.Further study is required to determine how natural substrates influence embryo physiology independent of water content.