Digital Aerial Surveys of Lesser Black-backed Gulls in the Bowland Fells SSSI/SPA
Natural England contracted APEM Group to determine the spatial extent and breeding population size of the Lesser Black-backed Gull (Larus...
APEM Group - Case Study
APEM Ltd, part of APEM Group, was commissioned by Natural England, via the Monitoring, evaluation and learning (MEL) facility managed for Defra by ICF, to deliver four digital aerial surveys across The Greater Wash Special Protection Area (SPA) and surrounding areas. The surveys aimed to assess the distribution and abundance of key marine bird species, building on earlier surveys. The study area included The Greater Wash SPA, The Wash SPA, and a 10 km seaward buffer.
Project Context
The Greater Wash, a 3,536 km² coastal area in eastern England, was designated an SPA in 2018 to protect key overwintering bird species. These include red-throated diver (Gavia stellata), common scoter (Melanitta nigra), and little gull (Hydrocoloeus minutus), which were the focus of this survey programme. The surveys were strategically timed to capture peak seasonal abundance: autumn for little gull, and winter for red-throated diver and common scoter.
Key Stats
- Survey period: Across 5 months of seasonal surveys
- Survey area: Greater Wash SPA, The Wash SPA, +10 km buffer
- Flight altitude: ~1,300 ft
- Resolution: 1.5 cm GSD
- Transects flown: 56 (3.5 km spacing)
- Images captured: ~86,000
- Wildlife sightings: ~110,000 individuals across 61 species/groups
- Positive images: ~14,000
Seals and Gulls
Project Challenges
The large survey area required the simultaneous deployment of two aircraft. APEM’s grid-based design ensured 10% site coverage while maintaining high-resolution imagery. In 2023, only Greater Wash imagery was analysed initially, with the remaining data processed in 2024. APEM prioritised rapid turnaround, completing analysis within two months by reallocating resources to meet client deadlines.
Solution
APEM’s experienced image analysts identified all three target species across all four surveys:
- Common scoter: 3,175 individuals (1,658 in autumn, 1,517 in winter)
- Red-throated diver: 2,402 individuals (907 in autumn, 1,495 in winter)
- Little gull: 533 individuals (459 in autumn, 74 in winter)
Survey timing aligned with expected seasonal peaks, validating the planning approach and enhancing understanding of species distribution within the SPA. The survey reports are currently being prepared and will be published in due course.
Intertidal Zone
Additional Support
This project demonstrates APEM’s ability to deliver large-scale, high-resolution aerial surveys for conservation purposes. Our approach ensures accurate, species-level data to support SPA management and conservation objectives.
Supporting Marine Conservation and Offshore Planning
As the UK continues to balance marine conservation with offshore development, APEM’s proven capability in delivering robust, high-quality data is critical. Our digital aerial survey expertise supports evidence-based decision-making for SPAs and marine planning. To learn how APEM can support your environmental monitoring needs, get in touch with our team.
Little Gull, Red Throated Diver and Common Scoter
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