Petroleum Crude Oil Vulnerability Index

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A. Exposure Potential

1. Primary foraging technique
(Check more than one if applicable)

Dives or is submersed in water
Dabbles under water
Probes mud or stalks
Skims surface of water
Does not forage in water

2. Time spent in or on water

Nearly always
Most of the time
Half the time
Less than half the time
Seldom or never

3. Escape behavior

Swims, but sometimes dives
Flies, but sometimes swims

4. Preening or grooming behavior

Preens or grooms feathers or fur
Does not preen or groom

5. Exposure of eggs

Eggs laid in water
Eggs laid near water
Eggs laid away from water, transfer from adult likely (e.g., waterbirds)
Eggs laid away from water, transfer from adult not likely (e.g., turtles, terrestrial birds)
Does not lay eggs or does not breed in study area

6. Use of urbanized areas or shipping channels.

Readily inhabits and/or forages in these areas
Occasionally utilizes these areas
Avoids these areas

7. Residency

Year-round resident (does not migrate)
Migrates within study area
Migrates beyond study area (present during breeding)
Migrates beyond study area (present during winter)
Transient (present during migration only)

8. Social structure

Highly colonial or gregarious
Semi-colonial or semi-gregarious

9. Range

Present throughout entire study area
Present throughout more than half of study area
Present throughout about half the study area
Present throughout less than half the study area
Present in small part of study area only

B. Sensitivity

1. Effect of oil on waterproofing/insulation

Difficult to regain waterproofing/insulation (cormorants, diving ducks, most mammals)
Able to regain waterproofing/insulation (shorebirds, upland birds, other ducks)
Waterproofing/insulation not greatly affected (reptiles, amphibians, seals, sea lions, cetaceans)

2. Feeding specialization

Highly specialized
Somewhat specialized
Moderately adaptable
Very adaptable

3. Ability to metabolize and clear hydrocarbons

Low (fish-eating birds)
Moderate (other birds and mammals, reptiles)
High (rodents and lagomorphs, gallinaceous birds)

C. Resilience of Population

1. Abundance in study area

Abundant (numerous in suitable habitat)
Common (certain to be in suitable habitat)
Uncommon (presence expected, but not a certainty)
Occasional (presence possible, but not expected)
Rare (not normally present)

2. Distribution outside of study area

Endemic to study area
Present outside of study area, but not abundant
Abundant outside of study area

3. Reproductive potential

Low (1-2 offspring/yr)
Moderate (3-4 offspring/yr)
High (>4 offspring/yr)

4. Age at first breeding

6+ yr
5 yr
4 yr
3 yr
1-2 yr

Click button to calculate the Vulnerability index Scores:

Vulnerability index Scores (Scale = 4 - 20)


Petroleum Crude Oil Vulnerability Score: View Rankings

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Ranking of Species Vulnerability Index Scores, From Highest to Lowest

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What do these scores mean?