DOI: 10.5061/dryad.jdfn2z3kj
title: Temperatures inside Little Penguin (Eudyptula minor) artificial nest habitats exceed upper thermal limits in a range-edge population

description: Rising global temperature will have profound impacts on species and
 ecosystem functioning. Species existing near their thermal thresholds will
 be particularly vulnerable to these changes, and those species that rely
 on, or preferentially use, artificial structures may face pronounced
 effects. Gaining insights into the anticipated climate changes, both
 present and future, is crucial for informing conservation practices and
 the utilisation of artificial structures in conservation efforts. Using
 three years of data, we quantified and compared the temperature of
 artificial nest boxes installed between 1986 and 2006 and natural nest
 burrows of a fringing population of Little Penguins existing at the
 north-western limit of their range. Nest boxes were ineffective at
 replicating conditions of natural nests, exhibiting consistently higher
 daily maximum temperature (~2°C) and exceeding upper thermoneutral limits
 for longer than natural nests. Fine-scale biotic and abiotic nest
 characteristics influenced maximum nest temperature and exposure duration.
 Simulated temperature increase of 2°C predicted an increase in the number
 of days exceeding hyperthermic conditions (≥35°C) by up to 49%. Such
 increases will expose penguins to potentially fatal thermal conditions,
 particularly during the late breeding and moulting phases of their annual
 cycle. This study revealed that current and future thermal environments of
 Little Penguin terrestrial habitat on Penguin Island can exceed
 physiological limits for this species. Intervention to improve artificial
 nests and better quantify consequences is urgently needed given recent
 estimates of a declining population and increasing risk of local
 extinction.
description: Our objective was to describe and quantify temperature in
 artificial nests and how they differ from natural nest burrows, examine
 the influence of climate and nest attributes (location and vegetation
 cover) on nest microclimate. To do this, we measured air temperature
 within artificial nest boxes and natural nests for 3.5 years from July
 2013 – January 2017. Nest
 Types <em>Nest Boxes:</em> Timber** nest
 boxes are broadly similar in design, with minor differences depending on
 the year of installation. The boxes are either square or rectangular in
 shape, with slight variations in timber thickness and entrance design
 (hole versus tunnel). Additionally, some boxes include ventilation holes
 on the sides, while others do not. <em>Natural
 Nests:</em> A total of 20 natural vegetation nests were located in
 2013 with an additional 33 nests identified and monitored in 2014, 2015
 and 2016 Nest
 characteristics data For each nest, a suite of nest
 habitat variables thought to influence nest temperature was recorded.
 These were stratified to represent (1) characteristics describing the
 position of the nest within the landscape, and (2) characteristics
 directly associated with the nest. Landscape position characteristics
 included topographical measurements (slope, aspect and elevation). Nest
 site measurements included physical attributes (relating to the dimensions
 or physical structure of a nest) and vegetation
 characteristics.  Field measurements of vegetation
 characteristics were measured between March 2013 to December 2016
 capturing seasonal and annual dynamics. To determine the spatial scale at
 which vegetation most strongly influences microclimate, cover was
 quantified for: (1) nest box lid cover (box cover; for nest boxes only),
 (2) within one meter of the nest (quadrat cover), and (3) in the broader
 surrounding habitat, within approximately four meters of the nest
 (vegetation cover). These measurements included a combination of visual
 cover estimates and quantitative estimations of digital images.
 Description of nest characteristic measurements recorded for both Natural nests and nest boxes <strong>Slope</strong> – Slope of the ground on which the nest is located (degrees)       <strong>Elevation</strong> – Elevation of the of the position where the nest is located (m)     <strong>Aspect</strong> – Aspect of the hill face on which the nest is located (degrees) <strong>Species Composition</strong> – Species of plant that dominated the vegetation surrounding or covering the nest (measured once annually during winter) <strong>Quadrat cover</strong> – Visual assessment of vegetation cover (%) within a circular plot (1 m diameter) centred over the nest, categorised into: 1 = &lt;5% cover, 2 = 5- 24% cover, 3 = 25 – 49% cover, 4 = 50 – 74% cover and 5 = 75 – 100% cover). (Measured 4 times annually during winter, spring, summer, autumn) <strong>Vegetation cover –</strong> Quantitative assessment of proportion green vegetation cover (%) within a rectangular quadrat centred over the nest site. Measured annually at the beginning of autumn for all boxes in 2013, 2014, 2015, and 2016. Natural burrows were included in 2015 and 2016. <strong>Entrance bearing</strong> – The bearing (degrees) recorded once only for boxes and annually in winter for natural nests Description of nest characteristic measurements for Natural nests only <strong>Bush wall –</strong> Thickness of vegetation measured from the nest cavity ‘ceiling’ to the outside edge of the vegetation (mm).  (Annual measurement during winter) <strong>Discrete bush –</strong> Natural nest is either an isolated bush or part of a larger vegetation patch. (Annual measurement during winter) <strong>Nest bush height –</strong> Maximum height of the vegetation directly over the nest (mm). (Annual measurement during winter) <strong>Nest bush length –</strong> Length of nest shrub from the edge containing the entrance to the opposite edge of bush (mm). (Annual measurement during winter) <strong>Nest bush width –</strong> Width of nest shrub (mm). (Annual measurement during winter) <strong>Cavity cover -</strong> Percentage vegetation directly over the nest cavity measured using a Gopro HERO4 camera positioned in the centre of the nest bowl facing upwards. (Bi-annual measurement in summer and winter) Description of nest characteristic measurements recorded for nest boxes only <strong>Box cover -</strong> Visual assessment of percentage of box lid covered by vegetation, categorised into: None = &lt;5% cover, Moderate = 5 – 74% cover and Full = 75 – 100% cover). Measured seasonally (winter, spring, summer, autumn) <strong>Vents</strong> - Presence or absence of ventilation holes Local weather data To account for the effect of local weather conditions (wind, ambient temperature, humidity) on nest temperature, half-hourly measurements of ambient temperature, relative humidity, wind speed and direction were sourced from the Bureau of Meteorology (BoM) at Garden Island meteorological station. From these we extracted the daily maximum temperature (°C), relative humidity (%), and the average wind speed (kph) and wind direction at four time points (06:00, 09:00, 12:00 and 15:00) for each sampling day. Wind direction was categorised as either ‘onshore’ or ‘offshore’. Wind speed between each timepoint was highly correlated and consequently only the windspeed and wind direction at 12:00 was retained to evaluate the effect of wind conditions on nest temperatures during the observed peak heat periods. Nest microclimate data Temperature (°C) and relative humidity (%) inside both natural nests and nest boxes at were recorded continuously at 30-minute intervals. As there were fewer loggers than sampled nests, loggers were rotated between nests over two and a half years with most nests containing a logger for approximately 12 months. To quantify nest temperatures, half-hourly temperature measurements were first averaged by hour for each nest site and sampling date. Half-hourly measurements of ambient temperature recorded at the BOM Garden Island weather station were also averaged by hour for each day. For each sampling date (24-hour period), we calculated the daily maximum, daily minimum, daily mean and temperature range for ambient and sample nests. Departure values were calculated for each sampling date and nest by subtracting the daily ambient measurement from the corresponding daily nest measurement. For nests that recorded temperatures ≥30°C or ≥35°C, we also calculated the total number of hours per day a nest recorded temperatures of 30°C or higher and 35°C or higher (exposure hours). Exploratory data analysis revealed a slight non-linear relationship between maximum nest temperature and maximum ambient temperature, with a minor change in the effect occurring around 25°C. To account for this, we introduced a categorical variable, hereafter referred to as ‘temperature category’, where sample dates were categorised according to whether the maximum ambient temperature exceeded 25°C or not.
description: # Temperatures inside Little Penguin (*Eudyptula minor*) artificial nest
 habitats exceed upper thermal limits in a range-edge population
 [https://doi.org/10.5061/dryad.jdfn2z3kj](https://doi.org/10.5061/dryad.jdfn2z3kj) ### Dataset overview This dataset includes data analysed for the manuscript "Temperatures inside Little Penguin (*Eudyptula minor*) artificial nest habitats exceed upper thermal limits in a range edge population". Summary: Our objective was to describe and quantify temperature in artificial nests and how they differ from natural nest burrows, examine the influence of climate and nest attributes (location and vegetation cover – see methods) on nest microclimate, and predict future nest temperatures under a 2°C climate change scenario. To do this, we measured air temperature within artificial nest boxes and natural nests for 3.5 years from July 2013 – January 2017. We compared nest microclimate with local meteorological conditions by sourcing half-hourly measurements of ambient temperature, relative humidity, precipitation, wind speed, and direction from the Bureau of Meteorology (BoM) station at Garden Island, 10 km north of Penguin Island To quantify nest temperatures, half-hourly temperature measurements were first averaged by hour for each nest site and sampling date. Half-hourly measurements of ambient temperature recorded at the BOM Garden Island weather station were also averaged by hour for each day. For each sampling date (24-hour period), we calculated the daily maximum, daily minimum, daily mean, and temperature range for ambient and sample nests. Departure values were calculated for each sampling date and nest by subtracting the daily ambient measurement from the corresponding daily nest measurement. For nests that recorded temperatures ≥30°C or ≥35°C, we also calculated the total number of hours per day a nest recorded temperatures of 30°C or higher and 35°C or higher (exposure hours). Exploratory data analysis revealed a slight non-linear relationship between maximum nest temperature and maximum ambient temperature, with a minor change in the effect occurring around 25°C. To account for this, we introduced a categorical variable, hereafter referred to as ‘temperature category’, where sample dates were categorised according to whether the maximum ambient temperature exceeded 25°C or not. ### **Sharing/Access information** Due to third-party data sharing agreements, vegetation cover data **"vegCover"**  within all files has been redacted but can be provided on reasonable request. In addition to nest data collected as part of this research, additional data were derived from the following sources: * Local meteorological conditions were sourced from the Bureau of Meteorology (BoM) station at Garden Island, Western Australia * Vegetation cover data was sourced from the Department of Biodiversity Conservation and Attractions, Western Australia ### **Description of the dataset and files** HoulryHumidTbl_redactedData.csv – This file contains summarised hourly temperature measurements and nest attributes for each sample nest. HourlyTempTbl_redactedData.csv - Summarised hourly Humidity measurements and nest attributes for each sample nest DailyTempNatVBox_redactedData.csv - Summarised Daily temperature measurements and local climate measurements for all natural and artificial nests  DailyNatTempTbl_redactedData.csv - Summarised Daily temperature measurements and nest site attributes for all sampled natural nests  DailyBoxTempTbl_redactedData.csv -  Summarised Daily temperature measurements and nest site attributes for all sampled artificial nests (nest boxes)  Column headings, descriptions, and abbreviations used in the data are described in the table below. | **Column Heading** | **Description and abbreviations** | **NA Values** | | :----------------- | :------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | :------------------------------------------------------------------------------------------------------- | | nest\_id | Unique identification code of sample nest | Data missing | | Year | Sample Year (2013 – 2016) – NA values are not applicable | Data missing | | Date | Sampling Date | Data missing | | Time | Hour of 24hour period (0 – 23) | Data missing | | nest\_type | Nest box or Natural Nest | Data missing | | Season | Season (Spring, Summer, Autumn, Winter) | Data missing | | NestRH | Relative humidity recorded within sample nest (%) | Data missing due to equipment failure | | NestTemp | Temperature recorded within sample nest (°C) | Data missing due to equipment failure | | Ambient\_Temp | Ambient Temperature recorded at Garden Island weather station (°C) | Data missing due to equipment failure | | Ambient\_RH | Relative Humidity recorded at Garden Island weather station (°C) | Data missing due to equipment failure | | WindSpeed | Average wind speed in kph recorded at Garden Island weather station | Data missing due to equipment failure | | WindTrue | wind direction recorded at Garden Island weather station in degrees (0-360) | Data missing due to equipment failure | | WindOn\_Off | Onshore = Wind passes over ocean towards land in an Easterly direction | Data missing due to equipment failure | | RH\_Depart | Difference between Ambient Relative Humidity and Nest relative humidity (%) | Data missing due to equipment failure | | Temp\_Depart | Difference between Ambient Temperature and nest temperature (°C) | Data missing due to equipment failure | | vegCover | Vegetation cover - proportion green vegetation cover (%) within a rectangular quadrat centred over the nest site. | Vegetation data has been removed due to a data sharing agreement with a 3rd party. Available on request. | | bushHgt | Nest bush height *(mm).* | Not applicable to the nest type (i.e. boxes) or season | | bushLth | Nest bush length (mm). | Not applicable to the nest type (i.e. boxes) or season | | bushWidth | Width of nest shrub (mm). (Annual measurement during winter) | Not applicable to the nest type (i.e. boxes) or season | | bushWallDepth | Thickness of vegetation measured from the nest cavity ‘ceiling’ to the outside edge of the vegetation (mm) | Not applicable to the nest type (i.e. boxes) or season | | entranceBearing | The bearing (degrees) recorded once only for boxes and annually in winter for natural nests | Not applicable to the nest type (i.e. boxes) or season | | SummerCavCvr | Percentage vegetation directly over the nest cavity during Summer | Not applicable to the nest type (i.e. boxes) or season | | WinterCavCvr | Percentage vegetation directly over the nest cavity during Winter | Not applicable to the nest type (i.e. boxes) or season | | AutumnBC | Nominal category (1 – 5) of cover based on percentage of box lid covered by vegetation during Autumn | Not applicable to the nest type (i.e. natural nest) or season | | SpringBC | Nominal category (1 – 5) of cover based on percentage of box lid covered by vegetation during Spring, | Not applicable to the nest type (i.e. natural nest) or season | | SummerBC | Nominal category (1 – 5) of cover based on percentage of box lid covered by vegetation during Summer, categorised into: None = &lt;5% cover, Moderate = 5 – 74% cover and Full = 75 – 100% cover. | Not applicable to the nest type (i.e. natural nest) or season | | WinterBC | Nominal category (1 – 5) of cover based on percentage of box lid covered by vegetation during Winter, categorised into: None = &lt;5% cover, Moderate = 5 – 74% cover and Full = 75 – 100% cover. | Not applicable to nest type (i.e. natural nest) or season | | MaxBC | Maximum annual cover from the seasonal measurements. Nominal category (1 – 5) | Not applicable to the nest type (i.e. natural nest) | | MaxBC\_2 | Maximum annual cover from the seasonal measurements categorised into: None = &lt;5% cover, Moderate = 5 – 74% cover and Full = 75 – 100% cover. | Not applicable to the nest type (i.e. natural nest) | | AutumnQC | Nominal category of cover during Autumn based on percentage of vegetation cover within a circular plot (1 m diameter) centred over the nest, categorised into: 1 = &lt;5% cover, 2 = 5- 24% cover, 3 = 25 – 49% cover, 4 = 50 – 74% cover and 5 = 75 – 100% cover | Not applicable to Season | | SpringQC | Nominal category of cover during Autumn based on percentage of vegetation cover within a circular plot (1 m diameter) centred over the nest, categorised into: 1 = &lt;5% cover, 2 = 5- 24% cover, 3 = 25 – 49% cover, 4 = 50 – 74% cover and 5 = 75 – 100% cover | Not applicable to Season | | SummerQC | Nominal category of cover during Autumn based on percentage of vegetation cover within a circular plot (1 m diameter) centred over the nest, categorised into: 1 = &lt;5% cover, 2 = 5- 24% cover, 3 = 25 – 49% cover, 4 = 50 – 74% cover and 5 = 75 – 100% cover | Not applicable to Season | | WinterQC | Nominal category of cover during Autumn based on percentage of vegetation cover within a circular plot (1 m diameter) centred over the nest, categorised into: 1 = &lt;5% cover, 2 = 5- 24% cover, 3 = 25 – 49% cover, 4 = 50 – 74% cover and 5 = 75 – 100% cover | Not applicable to Season | | MaxQC | Maximum annual cover from the seasonal measurements | Not applicable to Season | | SpeciesComp | Species of plant that dominated the vegetation surrounding or covering the nest. Categorised into: | Not applicable to Season | | elevation | Elevation of the position where the nest is located (m) | data missing | | aspect | Aspect of the hill face on which the nest is located (degrees) | data missing | | slope | Slope of the ground on which the nest is located (degrees) | data missing | | Vents | Presence or absence of ventilation holes | Not applicable to nest type (i.e. natural nest) | | Aspect\_NS | Aspect of the hill face on which the nest is located as North = Northerly Aspect; South = Southerly Aspect; NONE = flat ground |   | | NestTempMax | Highest Daily Temperature recorded in Nest | Data missing due to equipment failure | | NestTempMin | Lowest Daily Temperature recorded in Nest | Data missing due to equipment failure | | NestTempMean | Mean Daily Temperature recorded in Nest | Data missing due to equipment failure | | NestTempRange |  Daily Temperature range recorded in Nest | Data missing due to equipment failure | | AmbientTempMax | Maximum Daily ambient Temperature (°C) | Data missing due to equipment failure | | AmbientTempMin | Minimum Daily ambient Temperature (°C) | Data missing due to equipment failure | | AmbientTempMean | Mean Daily ambient Temperature (°C) | Data missing due to equipment failure | | AmbientTempRange | Daily ambient Temperature range (°C) | Data missing due to equipment failure | | TempMax\_Depart | Difference between the daily maximum ambient measurement from the corresponding daily nest measurement | Data missing due to equipment failure | | TempMin\_Depart | Difference between the daily minimum ambient measurement from the corresponding daily nest measurement | Data missing due to equipment failure | | TempMean\_Depart | Difference between the daily mean ambient measurement from the corresponding daily nest measurement | Data missing due to equipment failure | | TempRange\_Depart | Difference between the daily ambient range measurement from the corresponding daily nest measurement | Data missing due to equipment failure | | WindGen\_Dir\_6am | the general wind direction at 6am (Onshore = Wind passes over ocean towards land in an Easterly direction | Data missing due to equipment failure | | WindGen\_Dir\_9am | the general wind direction at 9am (Onshore = Wind passes over ocean towards land in an Easterly direction | Data missing due to equipment failure | | WindGen\_Dir\_12pm | the general wind direction at 12pm (Onshore = Wind passes over ocean towards land in an Easterly direction | Data missing due to equipment failure | | WindGen\_Dir\_3pm | the general wind direction at 3pm (Onshore = Wind passes over ocean towards land in an Easterly direction | Data missing due to equipment failure | | WindDir\_6am | the average wind direction (degrees) at 6am | Data missing due to equipment failure | | WindDir\_9am | the average wind direction (degrees) at 9am | Data missing due to equipment failure | | WindDir\_12pm | the average wind direction (degrees) at 12pm | Data missing due to equipment failure | | WindDir\_3pm | the average wind direction (degrees) at 3pm | Data missing due to equipment failure | | WindSpd\_6am | the average wind speed (kph) at 6am | Data missing due to equipment failure | | WindSpd\_9am | the average wind speed (kph) at 9am | Data missing due to equipment failure | | WindSpd\_12pm | the average wind speed (kph) at 12pm | Data missing due to equipment failure | | WindSpd\_3pm | the average wind speed (kph) at 3pm | Data missing due to equipment failure | | WindMean | Mean Wind Speed for 24-hour period of each sampling date | Data missing due to equipment failure | | AmbientRHMax | Maximum daily ambient Relative Humidity (%) | Data missing due to equipment failure | | AmbientRHMean | Minimum daily ambient Relative humidity (%) | Data missing due to equipment failure | | AmbientRHMin | Mean daily ambient Relative humidity (%) | Data missing due to equipment failure | | TempCat | category describing whether the maximum ambient temperature =&gt; 25°C or &lt;25°C. | Data missing due to equipment failure | | HRS\_30 | For nests that recorded temperatures ≥30°C, the total number of hours per day a nest recorded temperatures of 30°C or higher | Data missing due to equipment failure | | HRS\_35 | For nests that recorded temperatures ≥35°C, the total number of hours per day a nest recorded temperatures of 35°C or higher | Data missing due to equipment failure | ## Code/Software NA