Coastal Waterbird Survey Flashcards
What are the goals and objectives of the survey?
Goal: to assess the impacts of natural and human-induced environmental change on BC’s waterbird populations.
- Data collected is used to estimate population size and to assess population trends and distribution of coastal waterbirds in BC.
- Assess and monitor importance of individual sites
- Improve our understanding of waterbird ecology
What steps have been taken in the protocol to minimize different types of bias? State the potential bias and how it would affect the data/results, then state the ‘rule’ used to minimize this bias. Do this for as many types of bias mentioned in the protocol
Standardized protocol for all volunteers:
- Effort bias based on equipment used. Minimized by requiring surveyors to have high quality binoculars or spotting scope good for 500m from shore
- Timing bias : second sunday of each month or within 1-2 days
- TOD and tidal bias (close to shore for viewing): within 2 hours of high tide
- Weather bias (detectability) - conduct on days with reasonable weather conditions
- Activity bias - do not count flying birds
- Density bias - follow procedures for counting flocks
List the steps one can take to improve their accuracy when counting large flocks of birds (see Training Resources for Citizen Scientists: Estimating Shorebird Flock Size). List as many of the steps as possible (usually ½ mark each in an exam question)
- Choose a discrete flock where you can clearly see the edges
- Quickly photograph this flock and record the number of the photo for later.
- Begin at one end of the flock and count off a block of 50 birds. If the flock is large you might count off
100 birds, and for very large flocks scale up to blocks of 1000 birds. - Now, with the mental image of what 50, 100 or 1,000 birds looks like, count the number of blocks
until you reach the end of the flock. - Multiply the number of blocks by the number of birds per block for an estimate of the flock size.
- Repeat steps 1 through 5 on other flocks of different sizes.
- Back home, upload the photos on your computer and count the number of birds in the photo.
- Compare your estimates to the actual number in each photo.
This article included 4 additional tips to help improve your accuracy, describe these.
- On arrival at a site, complete a quick estimate so you have a working number in case the flock flies.
- If the birds are moving rapidly, it is easiest to count in the direction opposite to their movement.
- To estimate the proportion of two or more species in a mixed flock (e.g. Dunlin and Western
Sandpipers), conduct a series of counts of all individuals on a transect line from the front to the back
of the flock, only counting individuals on the imaginary line to estimate the ratio of Dunlin to
Western (see image below). Repeat this as many times as conditions allow (4‐5 minimum). - For photography, use appropriate start and end markers (e.g. eagles, buoys, driftwood, etc.). The
flock will need to be within ~150m using a 4‐5x optical zoom for this to be worth your while, and
ideally, a 10x optical zoom or higher is desirable to take images in which you can easily discern
individuals.
What are the 3 critical assumptions with relative abundance surveys
a. What do they really mean?
b. Please provide an example that does not satisfy each assumption.
i. for ‘environmental, biological, and sampling factors must be kept constant’, please provide an example for each factor.
- Same or comparable stat. methods
- Environmental, biological, and sampling factors are kept constant between surveys.
- Surveys are independent.
b:
1. A statistical modeling software is used to analyze data from one survey, but not from the other
- env: Surveys are done in different seasons
bio: activity bias - behavior alters visibility, taking samples at times when species are engaged in different activities.
sampling: different bait is used between - 2 surveys in adjacent areas. Methods used in survey 1 attract all of the animals to that area, drawing them out of the adjacent area.
