Term
| Known Fate and Nest Survival only focus on: |
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Definition
| telling you probability of surviving an interval |
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Term
| known fate deals with disappearances by |
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Definition
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Term
| known fate used for data sets where |
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Definition
| individuals are marked with radio-tags |
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Term
| Censoring- right and left |
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Definition
Censoring – (right censoring); when individuals are not accounted for in a interval (individual emigrated, radio failure, etc.)
Staggered entry – (left censoring); when capture occasions do not occur at one time and individuals are entered into the sample over several intervals |
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Term
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Definition
censoring:
Advantages
Censoring
Staggered entry
Identical to binomial estimator with no censoring or staggered entry
Disadvantages
No covariates
Typically not used in a likelihood framework |
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Term
| Kaplan-Meier calculation: |
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Definition
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Term
| Heisey-Fuller calculation |
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Definition
(exponential distribution)
# deaths/ #days alive
example:5 deaths
95 “live” days
Daily Survival Rate = 1-( 5/95)=0.9474 |
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Term
| Heisey-Fuller adv and disadvs |
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Definition
Advantages
Censoring
Staggered entry
Covariates
Likelihood based
Disadvantages
Assumes an exponential distribution
When assumptions are not met, can get quite different answer than from the simple binomial |
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Term
| Program MARK Known Fate LD |
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Definition
Each Interval LD
L= animal fate known (1) or not (0)
D= lived (0) or died (1)
Careful! |
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Term
| Program Mark Known Fate adv and disadvs |
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Definition
advantages:
Alternative models
Covariates
Model selection
Model averaging
Disadvantages: |
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Term
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Definition
Animals do not lose their tags
Radios do not fail (hahahaha)
No goodness of fit test for known fate models….. |
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Term
| Nest survival description |
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Definition
Typically used when radio-tracking is not done routinely of all animals on the same occasion
Times of mortalities are poorly estimated
“Ragged” telemetry data
Model daily survival, then use the product to estimate interval survival rate |
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Term
| nest survival adv adn disadvs |
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Definition
Advantages:
Timing of nest losses can be unknown
No assumption of constant daily nest survival
Flexibility to model daily nest survival rates
Model selection
Disadvantages:
no goodness of fit
need at least 30, large sample sizes |
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Term
| Nest Survival Assumptions |
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Definition
Nests are correctly aged when they are found
Nest fates are correctly determined
Nest discovery and check do not influence nest survival
Nest fates are independent
Homogeneity of daily nest survival rates |
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Term
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Definition
i=day nest was found
j=last day alive
k=last day checked (hatch or fail)
f= fate
1= fail
0= success |
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Term
| Nest survival recommendations: |
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Definition
1.Large samples of nest are needed to provide precise estimates (minimum 30)
2. Nest checks should be conducted at regular intervals to obtain reasonable encounter histories
3. Use meaningful covariates such as nest age or features of the nest-site |
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