Techniques and Technologies for Studying Seabirds Flashcards
1
Q
Why is understanding at-sea habitat use critical to understanding seabird biology, movement and conservation in seabirds?
A
Outside of the breeding system seabirds spend most of their time at sea.
2
Q
Movement
A
Any tracked movement that is not migration
3
Q
Migration
A
Implies periodic two way movement to and from a given area
4
Q
Why do seabirds migrate?
A
- To separate breeding and feeding grounds (some breeding grounds may not be as productive as feeding grounds)
- Follow environmental conditions and foraging movements
5
Q
What are the two different types of foraging movements?
A
- Pelagic hunters (not breeding)
- Central-place foragers (breeding)
6
Q
Describe central place foragers
A
Always return to a central place when foraging (“home-base”)
Why is this a huge constraint
7
Q
what can influence foraging movements?
A
Oceanography: Foraging movements are closely tied to physical oceanographic features (ex: fronts, upwellings, sea mounts etc.)
8
Q
Why study animal movement?
A
To understand:
- Distribution and habitat use
- Foraging search strategies
- Animal navigation
- Spread of diseases
- Conservation biology
9
Q
What are challenges in studying seabird movements?
A
- They live most of their lives offshore
- Most sampling is conducted at breeding locations (Why is this a problem?)
- Difficult to catch at foraging locations
- Differential habitat use by sex, age, and class (Breeding adults and chicks spend most of their time at the breeding colonies, juveniles and non-breeding adults spend most of their time at sea)
- Tags must be be light weight so that they do not weigh birds down
- Important movements occur at depth but observations take place at the surface
- Physical environment is hard on tracking instruments
10
Q
Banding
A
- Important for tracking same individual bird
- No data transmission (just recognition)
11
Q
What are some limitations of bird banding?
A
Banding is not an accurate depiction of birds full activity
12
Q
Time Depth Recorders (TDRs)
A
- Developed first in the 1960s (Gerry Kooyman)
- What depth is the bird diving at and at what time (the only info is time and depth)
13
Q
VHF Tags
A
- Radio tags (before GPS)
- Tag sends out signals that get picked up by a receiver at fixed stations when bird flies by (you are not actively tracking the bird)
14
Q
What are limitations of VHF tags
A
Low spatial resolution
15
Q
What are commonly used tagging technologies today?
A
- Satellite tags
- GPS tags
- GLS tags
- Activity loggers
- Accelerometers
- Magnetometers
16
Q
What are limitations of PTT tags?
A
- The battery life is not long
- They are big (limited to bigger bird species)
- Low / uneven temporal resolution
- Argos system is limited to the number of positional fixes that can be taken per day
- Positional accuracy of Argos varies
17
Q
Argos Satellites
A
- Provide info. on animal movement and oceanographic features
- Actively transmit data
- Data collection and relay system that provides global coverage by “piggy backing” on polar-orbiting satellites
- Used since late 1980s
- Provides data on wide variety of applications
18
Q
Icarus Satellite
A
- Actively transmits data
- International Cooperation for Animal Research Using Space
- Satellite based
- Tracks migratory patterns of animals
- Allows the use of trackers that do not require a strong signal and can therefore be smaller (Can tag and track smaller animals)
19
Q
Archival Tags
A
- Tags must be physically recovered (most likely during next breeding season)
- Record detailed movement or activity data (ex: speed, depth and temperature)
20
Q
GPS Tags
A
- High spatial resolution
- Archival (must be retrieved to collect data)
- Can be combined with Argos or GSM
21
Q
Geolocator Tags (GLS Tags)
A
- Utilize light to calculate birds longitude and latitude
- Can track seabird movements for long periods (several years)
- Not as accurate as GPS or ARGOS
- Cheap and small
22
Q
What are some limitations of GLS tags?
A
- Low spatial resolution
- Only good at measuring broad-scale migration patterns
23
Q
Activity or Immersion Loggers
A
- Wet/dry sensor
- Indicates if a bird is in flight or in water (foraging)
- Can be used with GPS tags to identify foraging locations
24
Q
What are some limitations of activity or immersion loggers?
A
Must be combined with tracking data to establish high resolution movements
25
Accelerometer
- Measures change in velocity of the body over time
- Provided detailed high resolution information on 3D movements
- Improvements in size and weight have allowed them to be deployed on smaller seabirds
26
What are some limitations of accelerometers?
- Limited battery life
- Short duration deployments only
27
What are accelerometers typically used for?
- Examine specific behaviors (ex: flapping flight)
- To estimate energetic expenditure
28
Magnetometers
- Can identify the heading of a bird (North or South)
- Ex: Albatross dynamic flight
29
What effects do tags have on seabirds?
Tags can affect:
- Movement
- Behavior
- Health
30
Explain why tagging is considered to be data rich?
- It is easier to get money (funding) for tagging seabirds (data collection) than it is to analyze that data
31
Describe stable isotope analysis in tissues
- Can be conducted on different tissues ( skin, egg yolk, bone etc.)
- Measurements of tissues from the same individual can be used to provide dietary information over different time scales
- Metabolically inactive tissues (hair, skin, whiskers, nails, feathers etc.) reflect diet only during growth period
32
How can stable isotopes be used to trace animal migrations?
- Foodweb isotopic signatures are reflected in the tissues of organisms
- Isotopic signatures can vary spatially
- Organisms moving between distinct foodwebs carry information on the location of previous feeding grounds for periods that depend on the turnover rates for the tissue of interest (ex: bones have a longer turnover rate than blood)
33
What is an isoscape?
A map that tells you weal habitat birds are feeding in
34
How can mercury be used to track habitat use?
- Methylmercury accumulates in aquatic but not terrestrial foods
- Can identify terrestrial vs. marine foraging habitats
35
Eularian tagging technique
- Fixed in space
- Can gain information about a large number of individuals at a particular location
36
Lagrangian tagging technique
- Moving with an individual
- Can gather information about a small number of individuals across a large area
37
What are the advantages of studying seabirds at breeding colonies?
- Gain information on how individual level behavior translates into population processes
38
What techniques can be used to study seabirds at breeding colonies?
- Nest balances
- Egg loggers
- Autonomous acoustic sensors
- Radar
39
Nest balances
- Remotely measures chick (or adult) mass between feedings (can quantify meal mass)
- Can learn about meal mass at different foraging locations for different trip durations when combined with tracking studies
40
Egg loggers
- Egg turning and incubation are critical to embryo development and hatching success (how is this different between species and how does it impact reproductive success)
- Developed using 3D accelerometers, magnetometers, and temperature loggers
41
Autonomous acoustic sensors
- Record vocalizations
- Can estimate abundances
42
Radar
- Can study movements of seabirds for many years
- Useful for nocturnal species that return to nest sites at night
- Can be used to identify bird species
