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Dallmann Laboratory

N. b.: Paint-marking the birds resident on the nest during placement of the artificial egg and thus distinguishing them from their naïve partners also permitted to examine differences displayed by a

4.2.2.1 Sampling and Recording Methods

“When deciding on systematic rules for recording behaviour, two levels of decision must be made. The first, which we refer to as sampling rules, specifies which subjects to watch and when. The second, which we refer to as recording rules, specifies how the behaviour is recorded.” (MARTIN & BATESON 1993, p. 84)

In definitions of various sampling and recording methods suggested by different authors, these

‘three decisions on two levels’ (1.a whom and 1.b when, 2. how) frequently appear incompletely separated. In the following paragraphs, the terms Focal-Animal Sampling and Focal-Group Sampling (‘whom to watch’) are briefly characterised, followed by LEHNER’s (1998) comprehensive but rather

‘integrative’ definitions of sampling methods. Focusing primarily on the ‘when’ (the second of MARTIN

& BATESON’s first-level decisions), LEHNER presents sampling methods as sub-categories of recording methods (MARTIN & BATESON’s second-level decision, i.e. ‘how’).

As the terms state and event come up in the following paragraphs, the difference is briefly recapitulated in box 4-1.

N.b.: In THISTHESIS, collection of behaviour data on video tapes was followed by two steps of data transcription: Primary transcriptions served to manually transfer taped information onto hard-copy matrices (sheets of paper), while secondary transcriptions involved entering data into the computer. Sampling and recording methods employed differed between these two steps. An overview of the sampling and recording methods used for each step is given in table 4-3.

States vs. Events

Most behaviours can be divided into two categories based on their relative duration (ALTMANN

1974; LEHNER 1998):

State: An ongoing behaviour; a behaviour that can be timed with a stopwatch (e.g., resting).

Postures12 (‘prone’, ‘up’) likewise constitute states (but see footnote).

Event: A momentary behaviour; a behaviour that happens so suddenly and/or fast that only its occurrence can be meaningfully recorded (e.g., headshakes). A change between states may also constitute an event (e.g., for flying birds: the take-off between sitting/ perching and flying).

Box 4-1: Recapitulation: States and Events.

12 Strictly speaking, posture constitutes a behaviour state as well. Given the fact, however, that the penguin is able to perform a great number of behaviours either while prone or while sitting/ standing, posture was considered a separate category.

13 also referred to as ‘Focal Sampling’ (MARTIN & BATESON 1993)

4.2.2.1.1 Focal-Animal and Focal-Group Sampling13

Following the terminology of MARTIN & BATESON (1993, p. 84; s.a.), the terms Focal-Animal Sampling and Focal-Group Sampling predominantly refer to the first of the first-level decisions (‘whom to watch’).

In Focal-Group Sampling, an entire group is in the focus of observations.

In Focal-Animal Sampling, a single individual is chosen, and their behaviour is in the focus of observations. In case of social/ agonistic interactions, these observations may or may not include the animal(s) interacting with the focal animal.

Although, to some extent, the choice of (number of) focal subjects determines the nature of the data collected as regards the ‘when’ and ‘how’, MARTIN & BATESON (1993, p. 85) stress that “any of the three different recording methods (Continuous Recording, Instantaneous Sampling or One-Zero Sampling) can be used when recording the behaviour of a single animal”.

4.2.2.1.2 Continuous Recording Sampling Method

Continuous Recording Sampling Methods (LEHNER 1998) are used to record a complete account of all behaviour units of interest; i.e. data on occurrence, duration and sequences of both states and events are obtained. These sampling methods provide the most complete and accurate data. In the field, they are usually only feasible when a limited number of behaviours are observed in a single individual (i.e., Focal-Animal Sampling; but see below).

All-Occurrences Sampling (LEHNER 1998; in THISTHESIS abbreviated to AOS) is one of the sampling methods subsumed under Continuous Recording. It serves to record all occurrences of a particular behaviour. According to LEHNER (1998, p. 197), All-Occurrences Sampling of selected behaviours is possible if the following conditions apply:

1. The animals and the behaviours are easily observed.

2. The behaviours have been carefully defined so that they are easily recognised.

3. The behaviours do not occur more often (or more rapidly) than the observer can record them.

Table 4-2: Numbers of Behaviour Recordings of Focal Animals Collected on Video-Tape in Five Groups of Incubating Adélie Penguins during Two Consecutive Field Seasons. Focal animals were ‘named’ alphanumerically, with A, B, C, X, Y representing the study groups, the first number referring to the nest and the second one to the bird currently incubating. 2000, 2001: year of data collection; FA: focal animal; no: no fieldwork possible for various reasons;

[group-nest]-3: unidentified incubator; vis: human visitation occurred; unvis: no human visitation occurred. (page 1 of 2)

Behaviour recordings obtained per Focal Animal (FA); with (purple) and without (turquoise) human visitation Day and

Month

FA (year) 12 Nov. 13 Nov. 14 Nov. 15 Nov. 16 Nov. 17 Nov. 18 Nov. 19 Nov. 20 Nov. 21 Nov. 22 Nov. 23 Nov. 24 Nov. 25 Nov. 26 Nov. 27 Nov. 28 Nov. 29 Nov. 30 Nov. 01 Dec. 02 Dec. 03 Dec. 04 Dec. sum recordings

obtained per FA A5-1 (2000) unvis no 1 1 no 1 1 1 no 1 1 1 1 1 no no 10

A5-2 (2000) unvis no no no 1 1 no 1 1 no 1 5

A5-3 (2000) unvis 1 1 1 no no no no no (3)

A6-1 (2000) unvis 1 no no 1 1 1 no 1 1 no 1 1 no 1 9

A6-2 (2000) unvis 1 no 1 1 no no 1 1 no no 5

A6-3 (2000) unvis 1 no no no 1 1 1 no no (4)

B3-1 (2000) vis 1 no no no 1 1 no no 3

B3-1 (2000) unvis 1 no no no 1 no no 2

B3-2 (2000) vis 1 no 1 1 no 1 1 no no no 5

B3-2 (2000) unvis no no 1 no 1 no no 2

B3-3 (2000) vis no no no 1 1 no 1 no 1 (4)

B3-3 (2000) unvis no no no 1 no 1 no (2)

B4-1 (2000) vis 1 1 no 1 1 no 1 1 no no no 6

B4-1 (2000) unvis 1 no no 1 no no no 2

B4-2 (2000) vis no no no 1 1 1 1 no 1 no 1 6

B4-2 (2000) unvis no no no 1 1 1 no 1 no 4

B33-1 (2000) vis no no no 1 no 1 no 1 3

B33-1 (2000) unvis no no no 1 no 1 no 2

B33-2 (2000) vis 1 1 no 1 1 no 1 1 no 1 1 1 no no 9

B33-2 (2000) unvis 1 no no 1 no 1 1 no no 4

C1-1 (2000) vis 1 1 no 1 1 no 1 1 no 1 1 no no 8

C1-1 (2000) unvis 1 no no 1 no 1 1 no no 4

C1-3 (2000) vis no no no 1 1 no 1 no 1 (4)

C1-3 (2000) unvis no no no 1 no 1 no (2)

C2-1 (2000) vis 1 1 no 1 no no 1 no 1 no 1 6

C2-1 (2000) unvis 1 no no no 1 no 1 no 3

C2-2 (2000) vis no 1 no 1 1 no 1 1 1 no no 6

C2-2 (2000) unvis no no 1 no 1 1 no no 3

C11-1 (2000) vis no no no 1 1 1 no 1 no 1 5

C11-1 (2000) unvis no no no 1 no 1 no 2

C11-2 (2000) vis 1 1 no 1 1 no 1 1 no 1 no no 7

C11-2 (2000) unvis 1 no no 1 no 1 1 no no 4

Table 4-2: Numbers of Behaviour Recordings of Focal Animals Collected on Video-Tape in Five Groups of Incubating Adélie Penguins during Two Consecutive Field Seasons. (page 2 of 2)

This method of sampling can provide accurate data on the following:

1. Frequency13 and rate14 of occurrence (and temporal changes in rate) of the selected behaviours.

2. Restricted sequencing15. 3. Behavioural synchrony16.

As for the video recordings obtained in THISSTUDY, the possibility to replay sequences if necessary made it possible to expand the number of behaviours and to transcribe and subsequently compare the behaviour of several individuals with respect to the same period of time. Of the examples listed above, only frequency and rate were relevant to THISSTUDY.

Focal-Group All-Occurrences Sampling was employed in the primary transcription (video data onto paper) of a selected behaviour event (headshakes) in the absence/ presence of one or three human visitors. For each 30 s sampling interval, frequency of headshakes was noted chronologically and individually, identifying the respective bird by nest location (for details s.b., section 4.3.2.3).

13 i.e., number of occurrences (absolute frequency) or proportion of occurrences (relative frequency) 14 i.e., frequency per time unit (e.g., number of occurrences per 30 s-interval)

15 not applicable to THISSTUDY

16 not applicable to THISSTUDY

Behaviour recordings obtained per Focal Animal (FA); with (purple) and without (turquoise) human visitation Day and

Month

FA (year) 12 Nov. 13 Nov. 14 Nov. 15 Nov. 16 Nov. 17 Nov. 18 Nov. 19 Nov. 20 Nov. 21 Nov. 22 Nov. 23 Nov. 24 Nov. 25 Nov. 26 Nov. 27 Nov. 28 Nov. 29 Nov. 30 Nov. 01 Dec. 02 Dec. 03 Dec. 04 Dec. sum recordings

obtained per FA

X1-1 (2001) vis 1 1 1 no no no 3

X1-1 (2001) unvis 2 1 2 no no no 5

X2-1 (2001) vis 1 1 1 no no no 3

X2-1 (2001) unvis 2 1 2 1 no no no 6

X2-2 (2001) vis no no no 1 1 2

X2-2 (2001) unvis no 1 no no 1 2 4

X3-1 (2001) vis 1 1 no no no 2

X3-1 (2001) unvis 2 1 no no no 3

X3-2 (2001) vis 1 no no no 1 1 3

X3-2 (2001) unvis 2 1 no 1 no no 1 2 7

Y4-1 (2001) vis 1 1 1 no no no 3

Y4-1 (2001) unvis 1 1 2 1 no no no 5

Y5-1 (2001) vis 1 1 1 no no no 3

Y5-1 (2001) unvis 1 1 2 1 no no no 5

Y5-2 (2001) vis no no no 1 1 2

Y5-2 (2001) unvis no 1 no no 1 2

Y6-1 (2001) vis 1 1 no no no 2

Y6-1 (2001) unvis 1 1 2 no no no 4

Y6-2 (2001) vis 1 no no no 1 1 3

Y6-2 (2001) unvis

2001: delayed arrival in the field

1 no 1 no no 1 end of

field-work

3 total sessions recorded of identifiable FAs: 195 (A: 29; B: 48; C: 48; X: 38; Y: 32)

Focal-Animal All-Occurrences Sampling was used in the primary transcription of focal-animal behaviour. The individual’s posture, their position relative to the camera angle and all behaviour elements were noted second by second. Numbers, movements and selected behaviours of stationary and passing conspecifics in the vicinity of the focal animal were likewise transcribed that way.

By allocating behaviour elements to behaviour systems, All-Occurrences Sampling was also used to gain information on distribution of behaviour systems within a session (behavioural topography, q.v.).

4.2.2.1.3 Time17-Sampling Methods

LEHNER (1998, p. 201f.) distinguishes two main sampling methods within Time Sampling.

Using Instantaneous/ Scan Sampling18, the observer scores an animal’s behaviour (or the behaviours of several animals) at predetermined ‘points’ in time, whereas One-Zero Sampling19 serves to record whether a behaviour state – or, less frequently, event – occurred (one) or did not occur (zero) during a sample interval delineated by points in time.

According to LEHNER (1998, p. 202), these methods are often used under the following conditions:

1. To gather data on a few behaviours while simultaneously sampling a relatively large group of individuals (e.g. studies of behavioural synchrony; daily activity patterns; percentage of time spent in behaviours of specific interest).

2. To gather data on a larger number of behaviours on a few individuals (e.g. juvenile females), than we can with continuous sampling methods (e.g. time budgets for an exhaustive list of mutually exclusive behaviours).

3. To maintain a high inter-observer reliability when several observers with varying levels of ability and experience are by necessity involved gathering data20.

4.2.2.1.4 Instantaneous-Scan Sampling

“Instantaneous Sampling can be used to obtain data from a large number of group members by observing each in turn. Moreover, if the behavior [sic] of all visible group (or subgroup) members are [sic] sampled within a very short time period the record approaches a simultaneous sample on all individuals.” (ALTMANN 1974, p. 258f.)

The major benefit of Instantaneous-Scan Sampling21 is the relative ease of recording data versus All-Occurrences Sampling. According to LEHNER (1998, p. 205), this method works well with behaviour states but is not recommended for use with events.

Focal-Group Instantaneous-Scan Sampling (ISS) was used to gather data on behaviour states and posture (prone, i.e. lying down, vs. sitting or standing) of groups of penguins in the absence/

17 The full term should by right of categorisational consistency read ‘Time Recording Sampling Methods’, as the term time refers to a way of recording (‘from time to time’ as opposed to ‘continuous’), rather than to a way of sampling.

18 also termed ‘time-sampling’, (HUTT & HUTT 1970), ‘point sampling’ (DUNBAR 1976), or ‘on-the-dot sampling’ (SLATER

1978)

19 also termed ‘time-sampling’ (HUTT & HUTT 1970), or ‘Hansen system’ (FIENBERG 1972 quoted in LEHNER 1998) 20 not applicable to THISSTUDY

21 To emphasise that the data presented in THISSTUDY represent ‘truly instantaneous’ samples for the entire group, the sampling method will be referred to as Instantaneous-Scan Sampling.

presence of one or three human visitors. Additionally, the numbers of conspecifics present inside the group or in its vicinity were transcribed.

With respect to focal animals, this method was not employed.

4.2.2.1.5 One-Zero Sampling

Focal-Group One-Zero Sampling (OZS, ALTMANN 1974) was used in secondary transcriptions to render focal-group data originally transcribed using All-Occurrences Sampling (behaviour event:

headshakes) compatible to the information obtained by Instantaneous-Scan Sampling for the same groups. One-Zero Sampling consisted of noting for each individual within the focal group, whether they had or had not performed at least one headshake per 30 s interval. This method was at this stage considered to yield more appropriate results, as it directly reflected the number of penguins reacting, rather than representing a mixture of ‘more penguins’ and ‘the same penguin more often’.

With respect to focal animals, this method was not employed.

4.2.2.1.6 Not quite a Sampling ‘Method’: Ad Libitum Sampling

“With Ad Lib. Sampling, it is rarely possible to determine which differences in data are due to true differences between individuals, age-sex classes, or behaviors [sic], and which due merely to biases in sampling. […] In any field study, some data probably will consist of such records, which may be of considerable use as illustrative material and because of their heuristic value in searching for ideas and in planning systematic sampling of behavior. Often, too, rare but significant events are recorded during such non-systematic sampling periods.” (ALTMANN 1974, p. 236f.)

In THISSTUDY, Ad Libitum Sampling was not used to obtain data on the behaviour of the study birds themselves but employed to additionally record inordinary and/ or infrequent events which occurred in the vicinity of (or in the air above) the study birds and which were considered likely to have a potential impact on the birds’ behaviour and/ or heart rate.

Table 4-3: Overview of Sampling and Recording Methods Used in THIS STUDY. I: primary data transcription (video data into hard-copy matrix); II: secondary data tanscription (hard-copy matrix into Excel/ SPSS spreadsheets).

Sampling Method Choice of Subjects Usage in this Study Continuous Recording

Sampling Method LEHNER (1998)

Focal Groups,

Focal Animals Data collection in the field (behaviour) Focal Groups Data transcription I: behaviour event –

headshakes Focal Animals

Data transcription I: posture, behaviour elements, conspecifics (number, behaviour, velocity of movement) 1. All-Occurrences Sampling

Focal Animals Data transcription I: behaviour systems Time Sampling

Methods LEHNER (1998)

Focal Groups Data transcriptions 1. Instantaneous-Scan

Sampling Focal Groups Data transcriptions I and II: posture, behaviour states, conspecifics (number) 2. One-Zero

Sampling Focal Groups Data transcription II: behaviour event – headshakes

Ad Lib. Sampling ALTMANN (1974)

opportunistic/

non-specific

Documentation of unusual or infrequent events/ disturbances

22 e.g., removal of a heavy load of snow from the roof of the tent 23 e.g., B3-3, 23.11.2000 – a session without human visitation