DisplacementAssessment:

ASSESSMENTDURINGTHEBREEDINGSEASON

FrancisDaunt

Marinebirdimpactassessmentguidanceworkshop

20February2020

Acknowledgements

• Kate Searle (CEH), Adam Butler (BioSS) and Deena Mobbs (CEH)

• Funded projects from Marine Scotland

• Project Steering Group members: MS, SNH, JNCC, NE, RSPB

Displacement in the breeding season

• Breeding seabirds may be displaced from favoured foraging habitats by Offshore Renewable Developments

• Potential for negative consequences on SPA populations

Displacement Matrix

Joint Statutory Nature Conservation Bodies (SNCB) Interim Displacement Advice Note (2017)

Density in footprint

x

Displacement rate

x

Mortality rate

Displacement Matrix calculation

SeabORD

Sub-lethal effects

Driver Behaviour Energetics

Demographic ratesPopulation size

Sub-lethal

SeabORD Individual-based model• Simulate foraging behaviour of individuals in accordance with seabird behaviour and

optimal foraging theory (maximising energy intake / minimising time spent foraging)

• Displacement: individuals relocate and experience patch depletion and competition effects whilst foraging in a location

• Barrier effects: Individuals incur additional flight costs

• Fate of individual birds experiencing displacement and barrier effects:- Effects on adult survival (via changes in body mass)- Effects on productivity

SeabORD Inputs• Bird utilisation distribution• Prey distribution• Displacement and barrier rate• Footprint shapefiles• ‘border’ width (km) to be added for OWF footprints• ‘buffer’ width (km) to be added to OWF footprints• Species-specific parameters:

- Adult and chick body mass- Adult and chick critical body mass- Length of season

- Adult DEE and chick energy requirement- Activity costs- Intake rates

SeabORD flight lines

SeabORD Worked Example

SeabORD Worked Example

SeabORD Worked Example

• Generates adult and chick masses and number of foraging flights per day

• Generates time budgets (time spent foraging and flying)

SeabORD Worked Example

SeabORD Limitations

• Chick-rearing period only• Simple flight lines• Only currently parameterised for 4 species: kittiwake, guillemot, razorbill, puffin• Processing time to run can be long• Requires initial calibration to set baseline conditions appropriately in line with

empirical observations of adult mass loss and productivity

How to use SeabORD in assessments• Where you have a defensible Utilisation Distribution of breeding birds:

• Run SeabORD

• Where this is absent:• Run SeabORD emulator to estimate mortality rate• Run SeabORD using a 'generic' bird UD (e.g. derived from models of

seabird distribution) to estimate mortality rate• Use mortality rate in displacement calculation:

densityxdisplacementratexmortalityrate

SeabORD emulator• Explanatory variable: mortality rate per individual in footprint

• Covariates (available everywhere)- Footprint distance to colony- Footprint alignment to colony- Density in footprint - Survival- Productivity

• Run SeabORD across the full range of each input to derive regression equation

• Use regression equation based on known covariates

How to use SeabORD in assessmentsMeanabundanceofbirdsinfootprint

From local at-sea surveys

From UD and colony count

SeabORD with UD derived from good local GPS

with UD derived from multi-site modelling of GPS data (e.g. Wakefield et al., 2017)

with UD derived from MERP at-sea survey maps & SNH apportioning

SeabORD Emulator n/a

SeabORD: integration of Collision

Driver Behaviour Energetics

Demographic ratesPopulation size

Sub-lethal

Density in footprint

x

Displacement rate

x

Mortality rate

Contribution of SeabORD to summer assessments• Current approaches use expert judgement to estimate

mortality rate of displaced birds

• SeabORD estimates mortality of displacement based on biological realism

• SeabORD is flexible in how it can be used, dependent on the availability of input data

• Key pointers on data gaps

• New version of SeabORD (available March) will integrate collision and displacement effects