{
  "abstract": "The relationship between earlier laying and higher breeding success is well‐established in avian species. However, a wide distribution of breeding timings is often maintained within a population, and the causes and consequences of this variation require further exploration, particularly as many avian species advance breeding phenology in response to climate change.\n\nUsing a 16‐year dataset combining colony observations and biologging of Manx shearwaters (Puffinus puffinus), we show that earlier laying does not always result in higher breeding success, with later laying becoming less costly in recent years.\n\nWe additionally report a slight advancement in breeding timing within breeding pairs, despite finding no temporal trends in spring bloom onset. Nonetheless, birds adjusted lay date in response to interannual variation in phytoplankton bloom timing, and years with stronger Celtic Sea blooms exhibited stronger selection for early breeding.\n\nBreeding timing was also influenced by repeatable individual differences in migratory behaviour, with birds undertaking generally earlier, shorter migrations to less southerly destinations laying earlier across years.\n\nHowever, lay date was not determined solely by individual behaviour. In this long‐lived species with stable pair bonds, the arrival date of the second‐returning bird constrained advancement in laying.\n\nThis study suggests that variation in breeding timing is maintained through the combined effects of fluctuating selection, persistent individual differences, variation in non‐breeding duration and pair‐level processes.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Biology University of Oxford Oxford UK",
    "Department of Animal and Plant Sciences University of Sheffield Sheffield UK",
    "Norwegian Institute for Nature Research Trondheim Norway",
    "School of Molecular and Life Sciences Curtin University Perth Western Australia Australia",
    "University of Lausanne Lausanne Switzerland",
    "School of Environmental Sciences University of Liverpool Liverpool UK",
    "Graduate School of Environmental Studies Nagoya University Nagoya Japan",
    "Department of Vertebrate Ecology and Zoology University of Gdańsk Gdańsk Poland"
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 13,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Katrina Siddiqi‐Davies",
      "orcid": "0000-0002-8965-7978"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Natasha Gillies"
    },
    {
      "affs": [
        0
      ],
      "name": "Hector Bailey"
    },
    {
      "affs": [
        0
      ],
      "name": "Sarah Bond"
    },
    {
      "affs": [
        0,
        2
      ],
      "name": "Annette Fayet",
      "orcid": "0000-0001-6373-0500"
    },
    {
      "affs": [
        0,
        3
      ],
      "name": "Holly Kirk"
    },
    {
      "affs": [
        0
      ],
      "name": "Lewis Lancaster‐Reeves"
    },
    {
      "affs": [
        0,
        4
      ],
      "name": "Joe Morford"
    },
    {
      "affs": [
        0,
        5
      ],
      "name": "Oliver Padget"
    },
    {
      "affs": [
        0,
        6
      ],
      "name": "Akiko Shoji"
    },
    {
      "affs": [
        0,
        7
      ],
      "name": "Martyna Syposz",
      "orcid": "0000-0002-6148-039X"
    },
    {
      "affs": [
        0,
        5
      ],
      "name": "Joe Wynn"
    },
    {
      "affs": [
        0
      ],
      "name": "Tim Guilford"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/e4kr206xf2gpr.bib",
  "cited_by": 0,
  "doi": "10.1111/1365-2656.70363",
  "fulltext_url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC13731836/",
  "id": "e4kr206xf2gpr",
  "issns": [
    "0021-8790",
    "1365-2656"
  ],
  "landing_url": "https://doi.org/10.1111/1365-2656.70363",
  "language": "en",
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "heading",
      "Behavioural Ecology"
    ],
    [
      "heading",
      "Research Article"
    ],
    [
      "openalex",
      "2303|Avian ecology and behavior"
    ]
  ],
  "openalex": "W7221338216",
  "pdf_url": "https://onlinelibrary.wiley.com/doi/pdfdirect/10.1111/1365-2656.70363",
  "pmcid": "PMC13731836",
  "pmid": "42856004",
  "published": "2026-10-10",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/e4kr206xf2gpr.ris",
  "sources": [
    {
      "first_seen": "2026-11-08T12:21:57Z",
      "native_id": "PMC13731836",
      "source": "pmc",
      "url": "https://doi.org/10.1111/1365-2656.70363"
    }
  ],
  "subjects": [
    {
      "field": "biology",
      "origin": "openalex:2303|Avian ecology and behavior",
      "subfield": "ecology"
    }
  ],
  "title": "Why don't all birds lay early? Causes and consequences of breeding timing for a long‐lived migratory seabird",
  "title_text": "Why don't all birds lay early? Causes and consequences of breeding timing for a long‐lived migratory seabird",
  "type": "peer-reviewed",
  "updated_at": "2026-11-08T12:21:57Z",
  "url": "https://research.draconitic.com/paper/e4kr206xf2gpr",
  "venue": "The Journal of Animal Ecology",
  "versions": []
}