Skip to main content
SpringerLink
Log in

Natural body size variation in seabirds provides a fundamental challenge for flight height determination by single-camera photogrammetry: a comment on Humphries et al. (2023)

  • Comment and reply
  • Published:
Marine Biology Aims and scope Submit manuscript

Abstract

Determining flight heights for seabirds is a crucial prerequisite for understanding collision risks associated with offshore wind farms and other human made infrastructure, but obtaining accurate and precise estimates of flight height distributions from observational data remains a challenge. Humphries et al. (Mar Biol 170:1–16, 2023) propose a workflow to determine flight heights of seabirds from digital aerial video images using single-camera photogrammetry. However, their workflow does not adequately consider the impact of uncertainty about seabird body sizes on individual flight height estimates. As a result the proposed method substantially underestimates the uncertainty of individual flight height estimates and yields biased estimates of both the proportion of birds at collision height, and average flight heights. The validation of the proposed method is insufficient and therefore unable to identify or quantify these shortcomings. Based on a review of seabird biometrics, we further argue that even when uncertainty in seabird body size is correctly propagated, the accuracy and precision of flight height estimates from single-camera photogrammetry data is fundamentally limited by the large natural body size variation of seabirds. Digital aerial surveys are an important observational tool to survey marine bird populations, but the workflow proposed by Humphries et al. (2023) for flight height estimation from single-camera digital aerial survey data is biased and does not sufficiently account for uncertainty, and we strongly advise against its use in the current form, for offshore development assessments.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4

References

  • Band W (2012) Using a collision risk model to assess bird collision risks for offshore wind farms. Report to strategic ornithological support services programme, project SOSS-02

  • Barrett R, Fieler R, Anker-Nilssen T, Rikardsen F (1985) Measurements and weight changes of Norwegian adult puffins Fratercula arctica and kittiwakes Rissa tridactyla during the breeding season. Ringing Migr 6:102–112

    Article  Google Scholar 

  • Borrmann RM, Phillips RA, Clay TA, Garthe S (2019) High foraging site fidelity and spatial segregation among individual great black-backed gulls. J Avian Biol 50

  • Buckland ST, Burt ML, Rexstad EA, Mellor M, Williams AE, Woodward R (2012) Aerial surveys of seabirds: the advent of digital methods. J Appl Ecol 49:960–967

    Article  Google Scholar 

  • Buonaccorsi JP (2010) Measurement error: models, methods, and applications. CRC Press, Boca Raton

    Book  Google Scholar 

  • Conover MR, Hunt Jr GL (1988) Sex ratios of North American gulls based on museum collections. Colon Waterbirds 38–45

  • Cook A, Ward R, Hansen W, Larsen L (2018) Estimating seabird flight height using LiDAR. Scott Mar Freshw Sci 9:1–52

    Google Scholar 

  • Coulson J, Butterfield J, Duncan N, Kearsey S, Monaghan P, Thomas C (1984) Origin and behavior of great black-backed gulls wintering in northeast England. Br Birds 77:1–11

    Google Scholar 

  • Coulson J, Thomas Cs, Butterfield J, Duncan N, Monaghan P, Shedden C (1983) The use of head and bill length to sex live gulls Laridae. Ibis 125:549–557

    Article  Google Scholar 

  • Cramp S, Simmons KEL, Brooks D, Collar N, Dunn E, Gillmor R, Hollom P, Hudson R, Nicholson E, Ogilvie M et al (1983) Handbook of the birds of Europe, the Middle East and North Africa. The Birds of the Western Palearctic: 3. Waders to Gulls

  • Croxall JP (1995) Sexual size dimorphism in seabirds. Oikos 73:399–403

    Article  Google Scholar 

  • Eck S, Töpfer T, Fiebig J, Heynen I, Fiedler W, Nicolai B, Elzen R, van den Winkler R, Woog F (2011) Measuring birds. Christ Media Natur, Minden, Germany

  • Fairbairn J, Shine R (1993) Patterns of sexual size dimorphism in seabirds of the southern hemisphere. Oikos 68:139–145

    Article  Google Scholar 

  • Hallgrimsson GT, Helgason HH, Palsdottir ES, Palsson S (2016) Sexing adult and fledgling lesser black-backed gulls from morphometrics. Ringing Migr 31:68–73

    Article  Google Scholar 

  • Harris M (1964) Measurements and weights of great black-backed gulls. Br Birds 57:71–75

    Google Scholar 

  • Harris M, Jones PH (1969) Sexual differences in measurements of herring and lesser black-backed gulls. Br Birds 62:129–133

    Google Scholar 

  • Harris MP, Tasker ML (1999) Conservation value of ringing seabirds in Britain and Ireland. Ringing Migr 19:95–106

    Article  Google Scholar 

  • Harwood AJP, Perrow MR, Berridge RJ (2018) Use of an optical rangefinder to assess the reliability of seabird flight heights from boat-based surveyors: implications for collision risk at offshore wind farms. J Field Ornithol 89:372–383

    Article  Google Scholar 

  • Helfenstein F, Danchin E, Wagner RH (2004) Assortative mating and sexual size dimorphism in black-legged kittiwakes. Waterbirds 27:350–354

    Article  Google Scholar 

  • Humphries GRW, Fail T, Watson M, Houghton W, Peters-Grundy R, Scott M, Thomson R, Keogan K, Webb A (2023) Aerial photogrammetry of seabirds from digital aerial video images using relative change in size to estimate flight height. Mar Biol 170:1–16

    Article  Google Scholar 

  • Ingolfsson A (1969) Sexual dimorphism of large gulls (Larus spp.). Auk 86:732–737

    Article  Google Scholar 

  • Johnston A, Cook ASCP, Wright LJ, Humphreys EM, Burton NHK (2014) Modelling flight heights of marine birds to more accurately assess collision risk with offshore wind turbines. J Appl Ecol 51:31–41

    Article  Google Scholar 

  • Ku HH (1966) Notes on the use of propagation of error formulas. J Res Natl Bureau Stand 70

  • Largey N, Cook AS, Thaxter CB, McCluskie A, Stokke Bå G, Wilson B, Masden EA (2021) Methods to quantify avian airspace use in relation to wind energy development. Ibis 163:747–764

    Article  Google Scholar 

  • Lo E (2005) Gaussian error propagation applied to ecological data: post-ice-storm-downed woody biomass. Ecol Monogr 75:451–466

    Article  Google Scholar 

  • Masden EA, Cook ASCP (2016) Avian collision risk models for wind energy impact assessments. Environ Impact Assess Rev 56:43–49

    Article  Google Scholar 

  • Masden EA, Cook AS, McCluskie A, Bouten W, Burton NH, Thaxter CB (2021) When speed matters: the importance of flight speed in an avian collision risk model. Environ Impact Assess Rev 90:106622

    Article  Google Scholar 

  • McGowan R, Zonfrillo B (1995) Pitfalls in sexing kittiwakes Rissa tridactyla on head+ bill length. Ringing Migr 16:124–126

    Article  Google Scholar 

  • McGregor RM, King S, Donovan CR, Caneco B, Webb A (2018) A stochastic collision risk model for seabirds in flight. Marine Scotland Science

  • Milner-Gulland E, Shea K (2017) Embracing uncertainty in applied ecology. J Appl Ecol 54:2063

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  • Monaghan P, Coulson J, Duncan N, Furness R, Shedden C, Thomas C (1983) The geographical variation of the herring gull Larus argentatus within Britain and in northern Europe; a biometrical approach. Ibis 125:412–417

    Article  Google Scholar 

  • Muusse M, Muusse T, Buijs R, Altenburg R, Gibbins C, Luijendijk B (2011) Phenotypic characteristics and moult commencement in breeding Dutch herring gulls Larus argentatus & lesser black-backed gulls L. fuscus. Seabird 24:42–59

    Article  Google Scholar 

  • Nakagawa S, Freckleton RP (2008) Missing inaction: the dangers of ignoring missing data. Trends Ecol Evol 23:592–596

    Article  PubMed  Google Scholar 

  • Okill J, Wanless S (1986) Weights and wing lengths of juvenile gannets Sula bassana from Noss and Ailsa Craig. Ringing Migr 7:125–129

    Article  Google Scholar 

  • Pacheco MLM, Tavecchia G, Igual JM, Alonso-Álvarez C, Arizaga J, Galarza A, Oro D, Martínez-Abraín A (2023) Yellow-legged gulls from the mediterranean are not only larger but also allometrically longer-winged than those from the Cantabrian-Atlantic. Ardeola 70

  • Parkes KC (1989) Sex ratios based on museum collections—a caution. Colon Waterbirds 12:130–131

    Article  Google Scholar 

  • Phillips EM, Horne JK, Zamon JE, Felis JJ, Adams J (2019) Does perspective matter? A case study comparing Eulerian and Lagrangian estimates of common murre (Uria aalge) distributions. Ecol Evol 9:4805–4819

    Article  PubMed  PubMed Central  Google Scholar 

  • Prinsloo N, Postma M, Ryan P, Coetzee M, De Bruyn P (2021) Estimating bird flight height using 3-D photogrammetry. J Zool 314:174–186

    Article  Google Scholar 

  • Redman KK (2001) Sexual differences in behaviour and morphology of northern gannets. PhD thesis, Durham University

  • Robertson GJ, Roul S, Allard KA, Pekarik C, Lavoie RA, Ellis JC, Perlut NG, Diamond AW, Benjamin N, Ronconi RA et al (2016) Morphological variation among herring gulls (Larus argentatus) and great black-backed gulls (Larus marinus) in eastern North America. Waterbirds 39:253–268

    Article  Google Scholar 

  • Ross-Smith VH, Thaxter CB, Masden EA, Shamoun-Baranes J, Burton NH, Wright LJ, Rehfisch MM, Johnston A (2016) Modelling flight heights of lesser black-backed gulls and great skuas from GPS: a bayesian approach. J Appl Ecol 53:1676–1685

    Article  Google Scholar 

  • Scherz JP (1974) Errors in photogrammetry. Int J Rock Mech Min Sci Geomech Abstr 11:A179

    Article  Google Scholar 

  • Searle KR, O’Brien SH, Jones EL, Cook ASCP, Trinder MN, McGregor RM, Donovan C, McCluskie A, Daunt F, Butler A (2023) A framework for improving treatment of uncertainty in offshore wind assessments for protected marine birds. ICES J Mar Sci

  • Sibly R, Jones P, Houston D (1987) The use of body dimensions of lesser black-backed gulls Larus fuscus to indicate size and to estimate body reserves. Funct Ecol 275–279

  • Sluys R (1982) Geographical variation of the kittiwake, Rissa tridactyla

  • Smith RD (1988) Age and sex-related differences in biometrics and moult of kittiwakes. Ringing Migr 9:44–48

    Article  Google Scholar 

  • Smouse PE, Focardi S, Moorcroft PR, Kie JG, Forester JD, Morales JM (2010) Stochastic modelling of animal movement. Philos Trans R Soc B Biol Sci 365:2201–2211

    Article  Google Scholar 

  • Stauss C, Bearhop S, Bodey T, Garthe S, Gunn C, Grecian W, Inger R, Knight M, Newton J, Patrick S et al (2012) Sex-specific foraging behaviour in northern gannets Morus bassanus: Incidence and implications. Mar Ecol Prog Ser 457:151–162

    Article  Google Scholar 

  • Stefanski LA (2000) Measurement error models. J Am Stat Assoc 95:1353–1358

    Article  Google Scholar 

  • Taylor J (1997) Introduction to error analysis, the study of uncertainties in physical measurements, 2nd edn. University Science Books, Sausalito

    Google Scholar 

  • Thaxter CB, Ross-Smith VH, Cook A (2016) How high do birds fly? A review of current datasets and an appraisal of current methodologies for collecting flight height data. BTO Research Report No. 666, British Trust for Ornithology; British Trust for Ornithology, Thetford, UK

  • Threlfall W, Jewer DD (1978) Notes on the standard body measurements of two populations of Herring Gulls (Larus argentatus). The Auk 749–753

  • Wanless S (1983) Seasonal variation in the numbers and condition of gannets Sula bassana dying on Ailsa Craig, Scotland. Bird Study 30:102–108

    Article  Google Scholar 

  • Wanless S, Okill J (1994) Body measurements and flight performance of adult and juvenile gannets Morus bassanus. Ringing Migr 15:101–103

    Article  Google Scholar 

Download references

Acknowledgements

The British and Irish Ringing Scheme is supported by the Joint Nature Conservation Committee and we thank the many hundreds of volunteers for collecting biometric data. We thank Alison Johnston, Niall Burton and three anonymous reviewers for comments on earlier drafts.

Author information

Author notes

  1. Aonghais S. C. P. Cook

    Present address: The Biodiversity Consultancy, Cambridge, CB2 1SJ, UK

Authors and Affiliations

  1. British Trust for Ornithology, Thetford, IP24 2PU, UK

    Philipp H. Boersch-Supan, Caroline H. Brighton, Chris B. Thaxter & Aonghais S. C. P. Cook

Authors
  1. Philipp H. Boersch-Supan
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Caroline H. Brighton
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Chris B. Thaxter
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Aonghais S. C. P. Cook
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Philipp H. Boersch-Supan.

Ethics declarations

Conflict of interest

The British Trust for Ornithology (BTO) has previously received funding from HiDef Aerial Surveying Ltd and other commercial entities in the marine survey sector. The literature review of seabird biometrics and ringing data analyses that formed the basis of this paper was funded through an entirely separate contract and project between BTO, Vattenfall Vindkraft AB and Spoor AS. Vattenfall Vindkraft AB and Spoor AS were not involved in the design, writing, conclusions or any other work related to this paper.

Ethical approval

No animals were handled for the sole purpose of this study. Ringing data from the British and Irish Ringing Scheme that are summarised in this study retrospectively were collected by trained bird ringers licensed by the British Trust for Ornithology following all relevant guidelines and regulations.

Additional information

Responsible Editor: V. Paiva .

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary Information

Below is the link to the electronic supplementary material.

Supplementary file1 (PDF 1098 KB)

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Boersch-Supan, P.H., Brighton, C.H., Thaxter, C.B. et al. Natural body size variation in seabirds provides a fundamental challenge for flight height determination by single-camera photogrammetry: a comment on Humphries et al. (2023). Mar Biol 171, 122 (2024). https://doi.org/10.1007/s00227-024-04396-4

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI: https://doi.org/10.1007/s00227-024-04396-4

Search

Navigation