A Deeper Statistical Examination of Arrival Dates of Migratory Breeding Birds in Relation to Global Climate Change

Using an 18-year dataset of arrival dates of 65 species of Maine migratory breeding birds, I take a deeper view of the data to ask questions about the shapes of the distribution. For each year, most species show a consistent right-skewed pattern of distribution, suggesting that selection is stronger...

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Main Author: W. Herbert Wilson
Format: Article
Language:English
Published: MDPI AG 2013-04-01
Series:Biology
Subjects:
Online Access:http://www.mdpi.com/2079-7737/2/2/742
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author W. Herbert Wilson
author_facet W. Herbert Wilson
author_sort W. Herbert Wilson
collection DOAJ
description Using an 18-year dataset of arrival dates of 65 species of Maine migratory breeding birds, I take a deeper view of the data to ask questions about the shapes of the distribution. For each year, most species show a consistent right-skewed pattern of distribution, suggesting that selection is stronger against individuals that arrive too early compared to those that arrive later. Distributions are consistently leptokurtic, indicating a narrow window of optimal arrival dates. Species that arrive earlier in the spring show higher skewness and kurtosis values. Nectarivorous species showed more pronounced skewness. Wintering area did not explain patterns of skewness or kurtosis. Deviations from average temperatures and the North Atlantic Oscillation index explained little variation in skewness and kurtosis. When arrival date distributions are broken down into different medians (e.g., 5% median and 75% median), stronger correlations emerge for portions of the distribution that are adjacent, suggesting species fine-tune the progress of their migration. Interspecific correlations for birds arriving around the same time are stronger for earliest migrants (the 25% median) compared to the true median and the 75% median.
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spelling doaj.art-08cabe1bf0eb4365957ad8ae3f5287162023-09-02T01:18:54ZengMDPI AGBiology2079-77372013-04-012274275410.3390/biology2020742A Deeper Statistical Examination of Arrival Dates of Migratory Breeding Birds in Relation to Global Climate ChangeW. Herbert WilsonUsing an 18-year dataset of arrival dates of 65 species of Maine migratory breeding birds, I take a deeper view of the data to ask questions about the shapes of the distribution. For each year, most species show a consistent right-skewed pattern of distribution, suggesting that selection is stronger against individuals that arrive too early compared to those that arrive later. Distributions are consistently leptokurtic, indicating a narrow window of optimal arrival dates. Species that arrive earlier in the spring show higher skewness and kurtosis values. Nectarivorous species showed more pronounced skewness. Wintering area did not explain patterns of skewness or kurtosis. Deviations from average temperatures and the North Atlantic Oscillation index explained little variation in skewness and kurtosis. When arrival date distributions are broken down into different medians (e.g., 5% median and 75% median), stronger correlations emerge for portions of the distribution that are adjacent, suggesting species fine-tune the progress of their migration. Interspecific correlations for birds arriving around the same time are stronger for earliest migrants (the 25% median) compared to the true median and the 75% median.http://www.mdpi.com/2079-7737/2/2/742birdsmigrationskewnesskurtosisarrival datesweatherclimate changephenology
spellingShingle W. Herbert Wilson
A Deeper Statistical Examination of Arrival Dates of Migratory Breeding Birds in Relation to Global Climate Change
Biology
birds
migration
skewness
kurtosis
arrival dates
weather
climate change
phenology
title A Deeper Statistical Examination of Arrival Dates of Migratory Breeding Birds in Relation to Global Climate Change
title_full A Deeper Statistical Examination of Arrival Dates of Migratory Breeding Birds in Relation to Global Climate Change
title_fullStr A Deeper Statistical Examination of Arrival Dates of Migratory Breeding Birds in Relation to Global Climate Change
title_full_unstemmed A Deeper Statistical Examination of Arrival Dates of Migratory Breeding Birds in Relation to Global Climate Change
title_short A Deeper Statistical Examination of Arrival Dates of Migratory Breeding Birds in Relation to Global Climate Change
title_sort deeper statistical examination of arrival dates of migratory breeding birds in relation to global climate change
topic birds
migration
skewness
kurtosis
arrival dates
weather
climate change
phenology
url http://www.mdpi.com/2079-7737/2/2/742
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