北極高緯度のシギ・チドリ類は同じ繁殖地に戻ることが少ない(Home advantage or pastures new? Shorebirds in the high Arctic rarely return to the same breeding ground)

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2026-09-15 マックス・プランク研究所

マックス・プランク動物行動研究所などの研究者は、北極高緯度地域で繁殖するシギ・チドリ類が、毎年同じ繁殖地に戻るとは限らないことを明らかにした。グリーンランド北東部で複数年にわたり個体を追跡した結果、成鳥・若鳥ともに繁殖地への帰還率が従来想定より低く、特に若鳥では広い範囲を移動して新たな繁殖地を選択する傾向が確認された。一般に渡り鳥は生まれた場所や前年の繁殖地へ戻る「出生地・繁殖地忠実性」が高いと考えられてきたが、北極圏の厳しい環境では、餌資源や積雪、融雪時期などの年ごとの変動に応じて繁殖地を柔軟に変える可能性がある。研究は、こうした移動性が気候変動下での適応能力を理解するうえで重要であり、特定の繁殖地だけを保全対象とする従来型の保全策では不十分となる可能性を示している。

北極高緯度のシギ・チドリ類は同じ繁殖地に戻ることが少ない(Home advantage or pastures new? Shorebirds in the high Arctic rarely return to the same breeding ground)
Pectoral sandpipers (Calidris melanotos) migrate long distances from the wintering grounds in the Southern Hemisphere to their breeding sites along the arctic shores. However, for breeding, they rarely return to the same area they bred before. © MPI for Biological Intelligence / Kaspar Delhey

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繁殖地への忠実性の世界的緯度低下は、単一の生物群系から生じている A global latitudinal decline in breeding site fidelity emerges from a single biome

Peter Santema, Eunbi Kwon, Luke Eberhart-Hertel, Mihai Valcu, Bart Kempenaers
Ecography  Published: 14 September 2026
DOI:https://doi.org/10.1002/ecog.08440

Abstract

Species that breed in multiple years can either return to the same location to reproduce between seasons or disperse to a different location. Previous studies have shown that breeding site fidelity varies with species- and individual-specific traits, but much of the observed variation remains unexplained. Breeding site fidelity may also vary latitudinally, given that key ecological factors relevant for breeding such as seasonality, resource availability, and habitat stability show strong latitudinal gradients. We examined variation in breeding site fidelity among shorebirds, using 189 estimates of local return rate from 120 populations of 55 species. We first show that there is a strong non-linear latitudinal pattern in breeding site fidelity, with return rates being stable at lower latitudes and progressively decreasing towards higher latitudes. We then show that this effect is driven entirely by the tundra biome: in the tundra – but not in other biomes – return rates decrease sharply with latitude, resulting in overall lower return rates in the tundra compared to other biomes. We suggest that the high inter-annual variability in local breeding conditions and short window for reproduction that characterize the tundra, especially at higher latitudes, favor breeding dispersal and hence lead to low site fidelity. Our findings show that an apparent global latitudinal trend in a life-history trait can be driven by a single biome.

生物環境工学
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