Bigg’s calls, including T08, & whistles?

Posted on by Scott Veirs Posted in Acoustic analysis, Bigg's, Network news, transient
Big Bigg’s breach in Elliott Bay, 2022
(courtesy Catherine Denardo and Mike Dougherty)

Thanks to a sighting of “large group of orcas” southbound in Haro Strait near Kelp Reef at 11:50 on Sunday (see this Orca Network public Facebook post or this private Facebook group post), Feb. 26, 2023, Orcasound listeners heard Bigg’s killer whale calls — and possibly whistles — on the Orcasound Lab hydrophone this week. Despite extremely rough conditions in the Strait, with sustained 30-40 knot winds howling out of the west-southwest and a strong ebb current, the whales were audible for almost an hour (~50-minute bout, starting at about 12:38 Pacific time).

Listen to a highlight clip:

1m25sec of faint Bigg’s killer whale sounds (local WordPress copy of file, .ogg format)
Direct link to the file within the orcasound data product archive (.ogg format)

Here’s a snapshot of the local conditions faced by the whales:

Wind speed data from Kelp Reef and the currents from Kellett Bluff (both in knots).

Overall, the signal to noise ratio was low with lots of surface wave and surge noise on the relatively shallow recent re-deployment at Orcasound Lab. At the time of the bout, the tidal height nearby (at Bedwell Harbour) was about +2 meters. Here’s a visualization of the bout in Audacity with preliminary annotations:

Audacity waveform and spectrogram for the 2/26/23 Bigg’s bout.

You can see in the label track that there were a few calls and/or whistles, a more intense set of signals at a higher rate, and then some faint final singals, each separated by about 10 minutes of ambient noise. During this period the whales were likely continuing to travel south, per the initial sighting and a few hearings from Fred Horn on the Lime Kiln hydrophone (possible faint calls at 12:42, then stronger calls at 13:34), also reported via Facebook posts.

Here is a recording of the full 50-min bout (29 MB, .ogg format):

And the associated label track with preliminary annotations (in case you want to download the audio and labels for further analysis in Audacity). As I’m relatively new to annotating Bigg’s KW calls, especially faint ones from whales that were likely a few kilometers from the Orcasound lab hydrophone on a stormy day, I’d value any comments regarding my annotations. Were those early signals really whistles, or just the fundamentals or strongest harmonics of Bigg’s KWs calling through the noise from a substantial distance? How often to Bigg’s KWs whistle, anyways?!

Here’s a screenshot of my favorite part, the highlight 1m25s-clip shared above:

It’s my favorite because I’m pretty sure a couple of the Bigg’s calls are the T08 call, based on the Bigg’s/Transient pulsed call examples that John Ford shared with Orcasound long ago. Interestingly, these recordings by Frank Thomsen from back in August, 1996, seem to have been organized by Volker Deeke, per this HTML that present the sound files:

Here’s hoping some of these historic call examples that John has accumulated during his career will soon surface in a new online catalogue of Bigg’s KW signals… Stay tuned and keep listening!

Finally, I noticed a couple potential “jingles” when scanning the Orcasound Lab recording for KW signals. You can have a listen here and here. To me it sounds like a glass bottle or a few glass shards getting tumbled in the wave surge on a windy day at Orcasound Lab. Please help us guess what is making them! And let us know if you think they sound like the notorious, mysterious “jingle” that has been heard around the Salish Sea over the years… Here are MANY examples that tricked the OrcaHello AI:

JINGLES

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