Larus armenicus

(last update: 7-9-2010)

Home

armenicus 1cy July
armenicus 1cy August
armenicus 1cy Sept
armenicus 1cy Oct
armenicus 1cy Nov
armenicus 1cy Dec

armenicus 2cy Jan
armenicus 2cy Febr
armenicus 2cy March
armenicus 2cy April
armenicus 2cy May
armenicus 2cy June
armenicus 2cy July
armenicus 2cy August
armenicus 2cy Sept
armenicus 2cy Oct
armenicus 2cy Nov
armenicus 2cy Dec

armenicus 3cy Jan
armenicus 3cy Febr
armenicus 3cy March
armenicus 3cy April
armenicus 3cy May
armenicus 3cy June
armenicus 3cy July
armenicus 3cy August
armenicus 3cy Sept
armenicus 3cy Oct
armenicus 3cy Nov
armenicus 3cy Dec

armenicus sub-ad Jan
armenicus sub-ad Febr
armenicus sub-ad March
armenicus sub-ad April
armenicus sub-ad May
armenicus sub-ad June
armenicus sub-ad July
armenicus sub-ad August
armenicus sub-ad Sept
armenicus sub-ad Oct
armenicus sub-ad Nov
armenicus sub-ad Dec

armenicus adult Jan
armenicus adult Febr
armenicus adult March
armenicus adult April
armenicus adult May
armenicus adult June
armenicus adult July
armenicus adult August
armenicus adult Sept
armenicus adult Oct
armenicus adult Nov
armenicus adult Dec

armenicus info
armenicus iris speckling
.

Fig 23: Sonogram of armenicus long call identifying various elements and parameters measured for analysis.

Sound recordings were made in all colonies, using Sony portable MiniDisk (MZ-R3) with Sennheiser System K6 and microphone module ME-67. Sonogrammes were created using Avisoft 3.4d. Analyses were only made for the “long calls” (as in Goethe 1982), which is the dominant call in breeding places. Sound samples from Tuz Golu and Van Golu were compared to michahellis from Spain, the Camarque and breeding birds from the upper Rhine. There is no certainty if all analyzed calls apply to different birds, as recordings were made in large colonies. Sample sizes are 80 armenicus (Tuz Golu 44, Van Golu 36); 61 michahellis (Spain, Camarque, upper Rhine).

behaviour and composition of long call in armenicus
For this analysis, only the long call of adult birds was used. The behaviour when giving this long call can be described in several steps:
- In the early stage the head is pointing vertically down to the ground, so the bill tip points at the feet (but the head does not touch the belly).
- Then, the head is raised upwards quickly and the long call is given with the bill pointing 90 degrees upwards in the air (like in fuscus) or with the bill in 45-60 degrees angle (like in argentatus), or an angle in between. These three positions of the bill were scored in Tuz Golu in frequencies 17:9:37 (n = 63). Hence, armenicus normally raises the bill higher in the iar than average argentatus. In this sample, 6 birds curved the wings slightly, but none of the birds expressed a long call with an albatross posture, like cachinnans do. In general, the long call in armenicus is most similar to that in michahellis and fuscus.

Long call display
In large white-headed gulls, the long call has a stereotype pattern: it starts with one, only rarely two long elements, then miau-calls, then an intermediate call, followed by 8 to 24 short elements (see Fig. 22). Long call vocalizations differed significantly from those of michahellis in 5 parameters measured sonographically (duration of first 8 short elements, frequency of miau-call and first short element, intensity distribution of harmonics and frequency modulation of miau-call), but differences were slight and gradual in nature. Several of these parameters may be related to body size, i.e. differences from michahellis may reflect smaller body size of armenicus.

The five differences between armenicus and michahellis long call (n = 141 call sequences):

1. Time of the first 8 short elements (and including the intervals in between): armenicus 1.7 sec; michahellis 2.1 sec (t-Test: p<0.001).

2. Highest frequency in first 'high note': armenicus 1.47 kHz; michahellis 1.31 kHz (t-Test: p<0.001).

3. Highest frequency in the first harmonic note of the miau-call: armenicus 1.32 kHz; michahellis 1.05 kHz (t-Test: p<0.001).

4. Intensity (stress) on the high note of the miau-call: 80% of michahellis put stress on the first high note, while armenicus spread the stress, with 20-40% of the birds stressing the first, second or third high note (t-Test: p<0.001).

5. Frequency distribution of miau-call (see Fig. 23), three classes are distinguished:
Class I: miau call flat, no modulation
Class II: miau call moderate modulation
Class III: miau call with strong frequency modulation / fluctuation.
The flat miau calls are found more often in michahellis (23%) than in armenicus (10%). Class III, where strong modulations can be heard in the miau call are very common in armenicus (80%) and uncommon in michahellis (15%). The distribution of these three classes is significantly different between teh taxa michahellis and armenicus (chi2-Test: p<0.001).

Summarizing, it can be stated that michahellis long call and armenicus long call are close, but measurable different from each other: armenicus has on average faster calls, with higher frequency (especially miau-calls) and it has miau-calls with more complex frequency sequences than we find in michahellis.