A challenge of warmer temperate winters: Long-term exposure to rain in cold temperatures drives higher thermogenic investment in a captive songbird

Long-term cold exposure induces many endotherms to invest in metabolic heat production, but how precipitation impacts thermogenic capacity in the context of different thermal conditions is largely undescribed in animals. In this study, songbirds (red crossbills; Loxia curvirostra) were held in warm (21 °C) or cold (6 °C) temperatures and either dry or rain precipitation treatments while experiencing a more northern or southern latitude photoperiod. We hypothesized that individuals experiencing winter rain would increase investment in thermogenic capacity, metabolic machinery, and catabolic enzymes to cope with increased thermogenic demands. Food intake and activity were monitored weekly, summit (Msum) and basal metabolic rates were measured in November, January, and February, and tissues were collected at the end of the study. Individuals held in cold rain treatments achieved the highest summit metabolic rate and had higher food intake, subcutaneous fat, heart mass, and metabolic enzyme..., , # Data from: A challenge of warmer temperate winters: Long-term exposure to rain in cold temperatures drives higher thermogenic investment in a captive songbird

Dataset DOI: [10.5061/dryad.6wwpzgncf](https://doi.org/10.5061/dryad.6wwpzgncf)

## Description of the data and file structure

In this experiment data was collected over the course of four months on 48 individual birds to determine how cold rain impacts thermogenic capacity and avian physiology. Birds were randomly assigned treatments of cold rain, cold dry, warm rain, and warm dry, and were assigned an ID number for the course of the experiment. Metabolic measurements were measured three times throughout the experiment, food intake & activity rates were measured daily and then averaged weekly, and morphometric data were collected once per week. 

### Files and variables

#### File: Msum_and_BMR_w_food_and_activity.csv

**Description:** Month and its interaction with weather variables were included as fixed effects to detect s...,