DOI: 10.5061/dryad.msbcc2gc8
title: First arrival dates of spring migratory birds in Mirnoye, Central Siberia

description: Despite the obvious shift in spring bird migration to earlier dates, the
 mechanism behind this process remains unclear, partly due to inappropriate
 climate predictors. Information on the influence of climate is not
 geographically representative, as it comes almost exclusively from the
 marginal parts of the continents. The objective of this study is to
 investigate the mechanism for determining the timing of spring terrestrial
 bird migration based on a new concept of environmental phenology and
 phenological navigation, using data from Central Siberia as an example. A
 literature review suggests that migrants follow the phenology of food
 resources, the dependence on which intensifies toward the end of migration
 with increasing seasonality of temperature conditions. We propose the
 concept of environmental phenology as a mediator between the influence of
 climate and the response of migrants. We defined the environmental
 phenology index as the average weighted temperature of the preceding days
 with weights decreasing exponentially in retrospect. Using original data
 from the first arrival dates of 145 species in Central Siberia from 1976
 to 2025, we demonstrated the effectiveness of the environmental phenology
 index in predicting arrival dates. This indicator reflects the
 accumulation of climate information by numerous ongoing phenological
 processes. Due to its high autocorrelation, it predicts future foraging
 conditions. Despite significant warming at the study site (0.60 degrees
 per decade), bird arrival dates in the studied community responded to
 warming with a slight shift toward earlier dates: on average, by -0.91
 days per degree annually and by -0. 86 days per decade. These estimates
 are lower than those known for other regions due to the pronounced
 continental climate and the steep rise in spring temperatures (1 degree in
 3 days). We believe the compensated share of this impact (the response to
 impact ratio) to be a more adequate measure of the organism's
 response to the impact. Based on the study results, we propose a mechanism
 of phenological navigation, in which a migrant at each stopover chooses
 whether to move on or wait for changes based on the relationship between
 environmental phenology and day length. This simple scheme opens new
 possibilities for comparing the phenological responses of different groups
 of organisms. The proposed index of environmental phenology is
 theoretically and practically substantiated, expands the understanding of
 the mechanism of phenological navigation and can be used to solve similar
 phenological issues.
description: # First arrival dates of spring migratory birds in Mirnoye, Central
 Siberia Dataset DOI:
 [10.5061/dryad.msbcc2gc8](https://doi.org/10.5061/dryad.msbcc2gc8) ##
 Description of the data and file structure **Bourski, O.V. Environmental
 phenology drives spring migration timing.** ***Journal of Animal
 Ecology*** Dataset of first arrival dates of bird species recorded at the
 Yenisei Ecological Station in Mirnoye (A.N. Severtsov Institute of Ecology
 and Evolution, Russian Academy of Sciences), 62°20′ N, 89°00′ E, in
 1976-2025 ### Files and variables #### File: EpDriverData.xlsx #####
 Variables * A, observation number * B, working species name abbreviation *
 C, serial number in the [HBW and BirdLife Taxonomic Checklist
 v7](http://datazone.birdlife.org/userfiles/file/Species/Taxonomy/HBW-BirdLife_Checklist_v5_Dec20.zip) * D, common name from there * E, scientific name from there * F, observation year * G, day of the first spring observation of the species [Julian date] No missing values included. ## Code/software MS Excel 2019