Assessing the nature of interactions between diving birds and underwater energy devices

1. Assessing the nature
of interactions
between diving birds
and underwater
energy devices
Cole, E., Shepard, E.L.C. Börger, L. & Waggitt, J.J.
- Alastair Marsh, 2019

2. Ramsey Sound, 2017
Complex tidal habitat
Seabirds Renewables
ENERGY
• Overlap between sites suitable
for device installation and
seabird foraging habitat.
HABITAT USE

3. ‘Ornithodolite’
• Laser-rangefinder binoculars
• 60+ survey days
• Record dives in space-time
• Identify high usage areas
Compare with
hydrographic models
METHODOLOGY

4. RESULTS
CURRENT

5. • Cormorants foraged close to the mainland in a highly restricted
area characterized by low current speeds
• Dive times coincided with periods of falling turbulence, 80% of
dives occurred when turbulence was <0.02 J kg−1
• Cormorants orientated into the flow of the current
• Selecting areas of low turbulence and orientating into the flow <
risk of collision with underwater turbines
RESULTS

6. METHODOLOGY
• Tag guillemots (AxyTREK): GPS, depth
+ acceleration
• Which hydrographic features are the
birds selecting?
• What are the benefits?
Puffin Island, Anglesey Common guillemot, Uria aalge

8. RESULTS
LAT
LON
Depth (m)
Frequency

9. RESULTS

10. RESULTS
• Guillemots foraged during all times
of the tide, often selecting areas
with moderate current speed + low
turbulence
• Foraged during the night (on
crustaceans), fish during the day
• How does the cost of diving vary
with tidal condition?

11. Anglesey, North Wales
Bull Bay
Point Lynas
Moelfre
METHODOLOGY

12. RESULTS

13. RESULTS
• Diving birds avoid areas of mean, high
current speed
• Usage of specific hydrographic features
(shear-lines, boils)
• Diving bouts concentrated near-shore

14. CONCLUSIONS
• SPACE-TIME PATTERNS: Where are birds foraging?
When are they foraging? Why?
• Are there any points of interest (hydrographic
features)?
HOW DO THESE BEHAVIOURS AFFECT INTERACTIONS
WITH MARINE RENEWABLES?

15. • Select specific hydro-features
• Low current speeds
• Low turbulence
• Orientate into the flow of the
current
• Use shear-lines
• Avoidance
• Dive deep (at depths ≥ devices)
• Overlap in space use > possible
interactions
• FAD
• Risk of birds being pulled into path
of moving components
• Disturbance/displacement
THE NATURE OF INTERACTIONS
BETWEEN SEABIRDS AND MARINE
RENEWABLES IS DEPENDENT ON VERY
FINE-SCALE CHOICES IN HABITAT USE.
CONCLUSIONS

16. NEXT STEPS……
• Provide data on more species to inform collision risk
assessments
• Identify high-usage areas for diving birds -> suggest
alternative site for energy extraction?
• Mitigation, predict effects ME devices may have on
diving seabirds

17. Thank you for listening <(“)
@Emma_Owl_Cole
Emma-Louise.Cole@Swansea.ac.uk