Communicative pulsed signals of beluga whales in the reproductive gathering off Solovetskii Island in the White Sea

Intraspecific variability in the “vowel”‐like sounds of beluga whales (Delphinapterus leucas): Intra‐ and interpopulation comparisons

“…Our previous studies have indicated that several similar call types are common to the Okhotsk Sea (Bel'kovitch and Sh'ekotov ), Chukotka (Belikov and Kirillova, unpublished data), and the White Sea (Belikov and Bel'kovich , ; Panova et al . ) beluga populations.…”

“…For example, low‐frequency whistles are not always easy to distinguish from some types of pulsed tones. (Compare whistles from Belikov and Bel'kovich and pulsed tones with high pulse repetition rate from Belikov and Bel'kovich ). In addition, whistles when coupled with pulsed sounds form biphonations, considered by some researchers as a separate category of “combined calls” (Karlsen et al .…”

“…) beluga populations. One of these call types, “vowels,” or “vowel”‐like sounds, is widespread in beluga vocalizations and amount to 10%–18% of the complete sound production in the White Sea and the Okhotsk Sea populations (Bel'kovitch and Sh'ekotov , Belikov and Bel'kovich , Panova et al . ).…”

Vocalizations of captive beluga whales, Delphinapterus leucas: Additional evidence for contact signature “mixed” calls in belugas

“…Another individual, a solitary female calf, produced harmonic sounds (Van Parijs et al . ) that appear similar to pulsed tones with high PRR (see Belikov and Bel'kovich ). Based on the age and status of the belugas (young animals and a mother–calf pair), Van Parijs et al .…”

“…The subjective classification of acoustic signals (except echolocation clicks) was performed by visual inspection of spectrograms (FFT size: 512, window type: Blackman, a 5 s viewing window with the frequency range up to 22 kHz). Based on our previous experience in classifying beluga sounds (Belikov and Bel'kovich , , , ; Panova et al . ) and the preliminary analysis of the audio recordings, the sounds were categorized as “squeaks,” “vowels,” “bleating,” and “others,” and as a “stereotyped” class that included tonal, pulsed, and mixed pulsed‐tonal calls with stable time‐and‐frequency parameters.…”