DOI: 10.5061/dryad.pnvx0k72q
title: High temperatures and poor habitat reduce nestling condition and survival in a tropical songbird

description: Climate change and habitat degradation are major threats to wildlife
 worldwide. Although developing animals are particularly sensitive to their
 impacts, with fitness consequences for individuals that cascade to
 population persistence, their combined effect and potential interaction
 are rarely considered. Here we address this in an indicator species for a
 biodiverse riparian ecosystem in Australia’s tropical savanna, an
 understudied region threatened by habitat loss and climate change. We
 investigate the effect of habitat, temperature and rainfall on nestling
 condition and subsequent survival in an individually-marked population of
 the Endangered purple-crowned fairy-wren (Malurus coronatus coronatus).
 Leveraging a high-quality 10-year dataset of nestling measurements, we
 control for pertinent factors influencing growth (e.g. food provisioned)
 and quantify short- and long-term survival with high accuracy. Higher
 ambient temperatures in the week after hatching reduced nestling body
 condition (mass relative to body size).
       Poor, degraded habitat
 (lower density of mid-story vegetation) decreased nestling body condition,
 regardless of temperature or rainfall. Lower body condition as a nestling
 did not affect survival to nutritional independence (12 weeks) but
 decreased survival from independence to adulthood (2 years). Poor habitat
 also directly decreased survival to adulthood, compounding this effect.
 Taken together, our results show that climate warming and habitat
 degradation are additive threats to nestling purple-crowned fairy-wrens
 that reduce survival to adulthood. Future research should address the
 mechanisms underlying the protective effect of high-quality habitat and
 explore how exposure to these threats during development affects fitness
 in other species. Policy implications: Our study shows that improving
 habitat quality is critical for riparian wildlife as the climate warms and
 that supporting long-term studies is important for detecting cryptic
 effects of anthropogenic threats. The Australian monsoonal savanna is
 projected to warm by 3.5°C by 2090, and our models predict an associated
 average 2.2% decrease in purple-crowned fairy-wren survival. This could be
 offset by a 7% increase in average habitat quality, underscoring the
 importance of high-density riparian habitat as a climate refuge.
 Conservation strategies for climate warming should protect high-quality
 habitat and improve low-quality patches, for example through effective
 fire management and reduction of high-intensity grazing.
description: # High temperatures and poor habitat reduce nestling condition and
 survival in a tropical songbird Dataset DOI:
 [10.5061/dryad.pnvx0k72q](https://doi.org/10.5061/dryad.pnvx0k72q) ##
 Description of the data and file structure This data was collected as part
 of a long-term study of the purple-crowned fairy-wren population at the
 Australian Wildlife Conservancy's Mornington Wildlife Sanctuary,
 Western Australia. ### Files and variables #### File:
 La_Porte_et_al._2026__JoAppEcol.csv **Description:**  ##### Variables *
 bird_id: individual identifier for each nestling * mom_id: genetic and
 social mother of the nestling * dad_id: genetic father of the nestling *
 nest_id: unique identifier of the nest in which the nestling hatched and
 was reared * year: Austral year (Jul st - Jun 30th) of first egg in the
 nestlings' nest * season: Wet season = Nov-Apr, Dry season = May-Oct
 * time_banded: Time of day the nestling was banded, weighed, and tarsus
 measured * mass: Mass of the nestling in grams * tarsus: Length of the
 nestling's left tarsus in milimeters * condition: Residuals of the
 following model: mass ~ tarsus + time + age + (1|observer ID) * sex:
 Genetic sex of the nestling * age: Age of the nestling at time of
 measurement (days) * observer: Unique identifier of the person who weighed
 the nestling and measured the tarsus length * brood_size: Total number of
 nestlings in the nest * helpers: Total number of subordinate helpers in
 the natal group * feed_rate: Feeding rate per hour * prey_size: Average
 prey size delivered to nest (in percent of adult bill size) *
 habitat_qual: Density of *Pandanus aquaticus* in the natal territory *
 rain3yn: Whether or not it rained in the 3 days preceeding measurement
 (inclusive) * rain7yn: Whether or not it rained in the 7 days preceeding
 measurement (inclusive) * rain3sum: Sum of the rainfall in the 3 days
 preceeding measurement * rain7sum: Sum of the rainfall in the 7 days
 preceeding measurement * Tmax3: Mean maximum temperature of the 3 days
 predeeding measurement (inclusive) (degrees C) * Tmax7: Mean maximum
 temperature of the 7 days predeeding measurement (inclusive) (degrees C) *
 Tmin3: Mean minimum temperature of the 3 days predeeding measurement
 (inclusive) (degrees C) * Tmin7: Mean minimum temperature of the 7 days
 predeeding measurement (inclusive) (degrees C) * surv_12_wks: Whether the
 nestling survived to 12 weeks * surv_2_yrs: Whether the nestling survived
 to 2 years * rain_12wks: Cumulative rain in the 12 weeks after hatching
 (mm) * rain_2yrs: Cumulative rain in the 2 years after hatching (mm) *
 mean_max_temp_12wks: Mean maximum temperature in the 12 weeks after
 hatching (degrees C) * mean_max_temp_2yrs: Mean maximum temperature in the
 2 years after hatching (degrees C) * days_40plus_12wks: Number of days
 over 40 degrees C in the 12 weeks after hatching *
 days_40plus_2yrs: Number of days over 40 degrees C in the 2 years after
 hatching