Posture
N. b.: Rather than being noted by frequency of single occurrences, the behaviour element ‘scan’
grouped events, e.g., duration spent performing agonistic behaviours, the time spent performing large and small head turns during vigilance) of selected behaviour elements (table 4-14) were calculated per interval. Posture and number of posture changes (from ‘prone’ to ‘up’ and vice versa) per interval were also entered into the matrix.
The procedure is illustrated in figure 4-10.
Figure 4-10: Example of 30 s of Secondary Transcription of Focal-Animal Behaviour, Posture, and Relative Orientation. Grey-shaded rows repeat entries of primary transcription (q.v.), unshaded rows illustrate conversion of information during secondary transcription with respect to analyses of behaviour elements and posture. Grey-shaded rows: Time (in seconds) is displayed in the second row, the third row codes for posture and orientation, the fifth row depicts behaviour states if necessary for assignment of elements, which are shown in the sixth row. The continuous flow of behaviour was broken down into 20 s-intervals (first row), and rates/ durations were calculated (fourth, seventh &
eighth rows). Arrows denote orientation relative to video camera. 01-30: seconds of a given minute; L: prone, S: up; Nm:
nest manipulation, Em: egg manipulation, sh: shuffle (rocking on egg), 1, 2, 3, 4: head turns of different extension and direction (unsuperscribed, these denote vigilance). R/ I: rest/ inactive, B: breeding, V: vigilance.
4.3.2.4.6 Behavioural and Postural Topography – Outlook on Secondary Transcription
As stated above, methods of transcription used for each level should be well in the readers’ minds when results are presented. Descriptions here are kept to a minimum, and details are provided in methodological preludes placed at the beginning of each of the results (sub-)chapters. A schematic overview of steps involved in data processing (transcriptions, analyses, and visualisation) is found at the end of this chapter (tab. 4-22).
For analyses of behavioural/ postural topography, secondary transcriptions were performed on 30 min stretches of focal-animal data (‘sessions’). With respect to data collected in 2001 (45 min per session), the behaviour and heart rate (q.v.) record available in primary transcriptions was
‘trimmed’ at the beginning and end so that, generally, the period of human visitation was situated approximately in the middle of the remaining record.
Secondary transcriptions focused on duration and distribution of each of the behaviour systems as well as both postures. The ‘flow’ of behaviour systems and postures before, during and after disturbance was assessed to examine changes in overall performance.
As mentioned in chapter 2, in this context, ‘flow’ combines the overall presence and prevalence (‘amount’/ extent) of behaviours belonging to a given behaviour system with the duration of phases found within that system as well as capturing changes between different behaviour systems (e.g., comfort 2 min, vigilance 20 s, comfort 10 s, vigilance 5 s) and ‘smoothness’ of transitions between systems (e.g., instant switches between systems, interruptions of one system by elements pertaining to another system, transitionary phases comprising elements of two different systems).
Taken together, these are referred to as the animal’s behavioural topography, and visualised as follows: Behaviour systems are coded numerically, with numbers attempting to reflect differences in focus and intensity (from ‘none or noncommittal’ during resting to ‘outward towards a likely
threatening stimulus’ during offensive agonistics). If plotted against time, each behaviour system is thus represented by a straight line on a system-specific horizon, while changes are indicated by the line ‘jumping’ from one horizon to the next.
Behavioural and postural topography (for heart rate, q.v.) were examined on three levels, viz., 1. qualitatively45 in terms of changes in intensity, and quantitatively in terms of number of birds displaying these changes (visual appraisal; key question: How many do respond?), 2. quantitatively on the level of occurrence/ prevalence of behaviour systems (comparison of magnitudes of changes in behaviour systems and posture; key question: How much do they respond?), and 3. quantitatively on the level of phases (distribution of phase/ state durations; key question: In what way do they respond?).
Each of these questions was addressed by looking at all focal birds together, and by examining differences between regimes. The chapter concludes with a comprehensive comparison of reactions to the different visiting regimes detected on the different levels.
n Qualitative Overview: Visual Appraisal of Changes in Behaviour and Posture during Human Visitation and/ or Conspecific Presence
Visual Appraisal constituted a qualitative, ‘graphical’ examination of changes in behaviour, posture, and heart rate (q.v.) before, during, and after human visitation. Following this, the question of consistency of these changes across focal animals was addressed quantitatively (key question:
How many?).
For visualisation, two Excel spreadsheets per session were created into which focal-animal parameters (1st spreadsheet) and disturbance parameters (2nd spreadsheet) were entered second-by-second. Focal-animal behaviour systems were assigned to topographical classes (tab. 5.3.1-2, chapter 5.3.1.1). These were complemented by focal-animal posture (prone or up;
per second) and heart rate (20 s-counts, q.v.). The second Excel spreadsheet contained information on conspecific and human disturbance (tab. 5.3.1-3, chapter 5.3.1.1). In addition to that, the rare recordings of skua (Catharacta spp.) presence on the ground, skua low46 overflights or aircraft noise were also noted in this spreadsheet.
Creation of Topography Charts: Each of the spreadsheets was split into three 10-minute sections so that the graphs created served to represent time before, during, and after human visitation.
Definitions: The definitions employed to assess behaviour and heart rate (q.v.) in visual appraisal are presented in box 5.3.1-1 (chapter 5.3.1.1).
Visiting Stage Performance Indicator Value (VS-PIV): The Visiting Stage Performance Indicator Value represented the stages of the visit unweighted by visitor number or conduct (tab. 5.3.1-3, chapter 5.3.1.1).
Conspecific Movement Measure (CMM): The Conspecific Movement Measure served to assess intensity and consistency of conspecific movement prior to human visitation for each session (tab. 5.3.1-4, chapter 5.3.1.1).
Visual Appraisal – Procedure: Each chart was scaled to fit an A3 sheet47. Using A3-printouts of the 51 sessions, 9 comportment48 parameters, comprising 7 behavioural parameters, as well as
45 i.e., looking for increases/ decreases without calculating the magnitude of these changes 46 Low overflights by Southern giant petrels (Macronectes giganteus) were not observed.
posture and heart rate were examined (tab. 5.3.1-5; chapter 5.3.1.1). To increase intra-observer reliability across sessions, visual appraisal of each of the 51 sessions was performed twice (1-51 first time, 1-51 second time), and the consensus was used for comparisons.
Before as well as after human visitation, visual appraisal was undertaken for five 2 min-intervals.
During human visitation, focal-animal behaviour, posture and heart rate (q.v.) were examined separately for each stage of the visit. Occurrences of natural disturbance (and aircraft noise – extremely rarely encountered) were likewise examined in that manner.
Colour Codes: Two sets of colour codes were used to depict ‘pre-visit status’ (blue-green colour range) and changes found during and after visitation (yellow-red colour range; see tabs. 5.3.1-6 and 5.3.1-7 in chapter 5.3.1.1).
n Quantitative Comparison of Prevalence of Behaviour Systems and Postures Exhibited before, during, and after Human Visitation
Comparison of prevalence of behaviour systems and one of the two postures49 before, during, and after human visitation examined between-period changes in proportional occurrence of each parameter (key question: How much?).
This was complemented by analyses of heart rate variation (q.v.) using 8 (descriptive) statistical parameters.
Friedman-tests were performed to examine consistency of direction of between-period changes, while boxplots visualised the magnitude of period differences found for each parameter.
n Distribution of Phase/ State Durations of Behaviour Systems and Postures before, during, and after Human Visitation
Distribution of phase/ state durations of behaviour phases, posture states and heart rate phases (q.v.) before, during, and after human visitation assessed changes in ‘flow’, by examining the duration and occurrence/ absence of phases and states for each period (key question: In what way?).
Behaviour:
For the purpose of THIS THESIS, the definitions pertaining to behaviour phases are presented in box 5.3.3-1(chapter 5.3.3.1).
Prior to determination of phase durations, the behaviour record was ‘condensed’ using a step-wise procedure (box 5.3.1-2 in chapter 5.3.3.1).
Period differences were examined after overlaps (i.e. phases across period boundaries) had been accommodated by assigning the entire phase to the period within which its greater proportion50 had occurred.
Behaviour phase durations were assigned to three duration classes, each of which was divided into three subclasses (tab. 5.3.3-1; chapter 5.3.3.1).
47 An example is presented in chapter 5.3.1.1, fig. 5.3.1-2; all graphs are available in appendix 5.3.1-1.
48 In THISTHESIS, the term ‘comportment’ is employed to summarily refer to behaviour, posture, and heart rate.
49 which were mutually exclusive (i.e., the bird could be either prone or up)
Posture:
Posture state was classified as either ‘prone’ or ‘up’ (the latter combining sitting and standing postures). Overlaps regularly reached far into the following period(s). Rather than trying to assign them to any one period, these were included in analyses of change frequencies only, but did not feature in analyses of state durations.
Posture state durations were likewise assigned to three duration classes, each of which was divided into three subclasses (tab. 5.3.3-2; chapter 5.3.3.1). Due to their greater range, class borders differ from those chosen for behaviour phases.
4.3.2.4.7 Out-of-sight Time and Missing Data
The behaviour of a focal animal was at times impossible to transcribe, basically for the same reasons as stated with respect to focal-group transcriptions (camera vibrations, bird’s head down and back to observer, bird hidden by conspecifics). Periods of ‘intranscribability’ ranged from 1 s (e.g., a passing conspecific) to the entire recording session (e.g., a passive conspecific).
Out-of-sight time was noted in the hard-copy matrix. It was transcribed in accordance with the rules outlined in appendix 4-1.
With respect to behaviour elements, missing single seconds were ‘extrapolated51’ if the behaviour before and after them was identical. Whenever the behaviour elements differed in intensity but belonged to the same behaviour system (e.g., alternate stare and sideways stare are both agonistic elements, with the former being more intense), the second in question was awarded to the less intense category. If behaviour systems before and after were different, however, the second was recorded as ‘unaccounted for’. Likewise, no attempts were undertaken to ‘guess’ the contents of longer stretches of invisibility. Periods of intermittent visibility (generally caused by moving conspecifics) were included if time accounted for exceeded 2 s, was at least as long as the time unaccounted for on one side and at the same time longer than that unaccounted for on the other (e.g., 4 s of invisibility, followed by 4 s of visibility, followed by 2 s of invisibility). Periods unaccounted for were summed up per interval, and the entire 20 s-interval was discarded if it contained less than 10 s of visible behaviour.
As for posture, missing data only occurred at the beginning or end of sessions so that no rules for extrapolation needed to be devised for evaluation in conjunction with behaviour elements or behavioural topography (q.v.).
Concerning behavioural topography, missing behaviour data were coded as 0 (zero) to allow for visual assessment of reliability of the remaining behaviour. Rules for extrapolation/ inclusion were identical to those outlined for behaviour elements.
In the topography charts (behaviour), any missing seconds have been left unchanged. Stretches of missing data are indicated by cross-hatched blocks.
N.b.: For tabulated visual appraisal of changes in the different behaviour systems and posture (and heart rate, q.v.), the term ‘n.a.’ (not applicable) was used to indicate either that the focal animal had not been seen in the respective interval or that the behaviour system focused on had not been observed throughout the session.
50 to adjust for different recording times per period 51 read: ignored
For quantitative comparison of prevalence (behaviour), any missing seconds were left unchanged and thus did not enter calculations.
With respect to phase durations (behaviour), one and two missing seconds enclosed in phases or interruptions were treated like ‘impurities’ (box 5.5.5-1; chapter 5.3.3.1). No attempt was undertaken to assign longer stretches of missing data.
Phases bordering onto missing data were only included in counts for phase durations, if they exceeded 20 s. Rules employed to accommodate missing behaviour data during evaluations of phase durations are explained in box 4-3).
Box 4-3: Rules Employed to Accommodate Missing Behaviour Data During Evaluations of Phase Durations. A series of three identical capital letters denotes a phase (successive behaviour elements pertaining to the same behaviour system: AAA). A series of constantly changing elements pertaining to different behaviour systems codes for an interruption (DEF). M: missing data; A, B, C, D, E, F: different behaviour systems; (A)A: 1 s or 2 s of behaviour system A.
Missing Data
AAA M(M) AAA è M à A (one long phase) AAA M(M) CCC è M à C (phase C is extended) DEF M(M) DEF è M à DEF (interruption is extended) (A)A M A(A) è M à A (one long phase)
(A)A M C(C) è M à C (phase C is extended) (D)E M F(E) è M à DEF (interruption is extended)
(A)A MM A(A) è A à M (missing data are extended on both sides)
(A)A MM C(C) è A(A) and C(C) à M (missing data are extended on both sides) (D)E MM F(E) è (D)E and F(E) à M (missing data are extended on both sides)
N.b.: Phases bordering onto missing data were only included in counts for phase durations, if