Orca bioacoustic nomenclature

With inspiration from Phil Karlton’s wise saying “There are only two hard things in Computer Science: cache invalidation and naming things," let's try to reach wiki-consensus on orca bioacoustic nomenclature!

Orca signals

The three types of vocalizations produced by killer whales:

• call (aka "pulsed call" or "pulsed signal")
  • signal consists of pulses generated at repetition rates of ~250-2000 pulses/s (Ford, 1987)
  • characterized by a fundamental frequency and harmonics (therefore more complex than a whistle)
  • typical duration and bandwidth: most ~0.5-1.5s, but range of 5 milliseconds to 10s (Ford, 1987); 200-20,000 Hz (Ford, 1987 says: "primary energy 1-6kHz, with some high-frequency components up to 30kHz)
  • stereotyped calls (repeated and recognizable)
  • variable calls (not stereotyped)
  • biphonic call = a call with two simultaneous, independently-modulated fundamental frequencies
  • repertoire = stereotyped calls of a group
• whistle
  • a single sinusoid with varying frequency ("for the most part" say Brown and Miller, 2007)
  • "non-pulsed or continuous waveform... a single, narrowband tone with little or no harmonic or sideband structure" ... and "extreme structural variability" (Ford, 1987)
  • typical duration and bandwidth: ~1-10 s; 1000-20,000 Hz
• click (aka "echolocation" or "echolocation signal" or "biosonar")
  • a short, broadband pulse
  • typical duration and bandwidth: 0.1-25 milliseconds (Ford, 1987); 100-100,000 Hz
  • impulse train = a series of broadband pulses
    • slow clicks = impulse train with inter-click interval (ICI) > 1 second
    • fast clicks = impulse train with ICI < 1 second
    • buzz = impulse train with ICI < 0.1 second

Other sounds that indicate the presence of killer whales:

• percussive
  • impact of pectoral fin or tail on sea surface
  • impact of body on sea surface (e.g. upon breaching or porpoising)
• cavitation
  • caused by fluke during rapid acceleration (e.g. during Bigg's predation events)
  • caused by tail strike (used by Icelandic or Norwegian KWs to stun herring)
• predation
  • caused by the jaw closing rapidly (e.g. a SRKW capturing a salmon)

With consideration of at least:

• Brown and Miller (2007)

Orcas

Groups

• matriline (aka "matrilineal line") = group from the same mother
• pod = group of several matrilines
• clan = group of pods that share calls

Ecotypes of the Northeast Pacific

• SRKWs = Southern Resident Killer Whales
  • J, K, and L pods
• NRKWs = Northern Resident Killer Whales
  • Many pods...
• Bigg's = West Coast Transient Killer Whales
• Offshores