A Humpback With 11 Birds in His Mouth?

A Humpback With 11 Birds in His Mouth?
Humpback Whales and Their Bycatch

Over the years we at MERS have documented several cases of Humpback Whale bycatch; that is other animals that inadvertently end up in their mouths. This often occurs because Humpback Whales approach dense schools of Pacific Herring at great speed while other species are also feeding on them.

Juvenile Pacific Herring being pushed to the surface by Common Murres (diving birds) feeding on them from below. Gulls feeding on the Herring from above.

The other animals can thereby end up engulfed with the Herring. Then what happens? Consider that anything the size of a Gull or larger cannot be swallowed since the throats of Humpbacks are narrow and because, as baleen whales, they do not have teeth for chewing prey into smaller pieces.

We’ve previously shared the footage below of a Pacific Harbour Seal escaping from the mouth of a trap-feeding Humpback Whale. 

Video by Gord Thompson and Dennis and Stephanie Parsons.

We’ve also documented Humpback Whales opening their mouths to release birds like Common Murres. See photos below of a Common Murre escaping from Guardian the Humpback Whale’s mouth.

On many occasions, we have also documented bycaught Gulls. The afternoon of October 18th was no exception. 

From our research vessel Merlin we noticed in the distance an adult Humpback we know as Backsplash lunge feed at the surface on a large school of Herring that was being fed on from below the surface by Common Murres and from above by Herring and California Gulls.

When we arrived about three minutes later Backsplash was slowly circling the remains of the school of Herring and then lunged on it again, effectively capturing all or most of the remaining fish that were left over from the first lunge. Seconds later Backsplash opened his mouth at the surface, vigorously shook his upper jaw and 11 Gulls came floating up to the surface.

By-caught Gulls discarded from Backsplash’s mouth. Note the Herring scales on the surface. Photo ©Jared Towers, MERS. 

We approached the scene and could see all Gulls were completely saturated – 9 appeared dead (from impact or drowning), and 2 were clinging to what appeared to be their last moments alive. We immediately grabbed the two survivors, both immature Herring Gulls, and wrapped them in a dry towel that I happened to have aboard.

Elysanne Durand drying and warming the two immature Herring Gulls. ©Jared Towers, MERS.

We then noticed that one of the birds we previously thought was dead was resting itself on the floating body or another. There was no room in the towel for this bird, a young California Gull, so I texted our colleagues at nearby OrcaLab on Hanson Island and we raced over for some support.

Gulls that had been in Backsplash’s mouth. Photo ©Jared Towers, MERS.

Moments later we were met on shore with towels and over the next little while dried off the birds while sitting next to the wood stove. We ended up leaving one of the Herring Gulls and the California Gull with our friends at OrcaLab and took the other Herring Gull back home to Alert Bay.

John Totterdel picking up the immature California Gull. Photo ©Jared Towers, MERS..

Once completely dry all birds were released at the shoreline. They each took to the water and then the sky, although the final fate of the poor California Gull is apparently unknown because it subsequently escaped attack by a Bald Eagle but then moved out of sight while the hunt was still in progress, as if being captured by a Humpback Whale wasn’t already enough!

I’m a strong believer that we should always be conscious of our impact on the environment and its inhabitants and this often means not interfering in interactions between predators and prey. However, in a case such as this where the by-product of a feeding predator happens to be some incidentally captured Gulls I have always felt compelled to help out, even though the Gulls typically appear resentful and aggressive as soon as they are warm and dry again.

JT


Read more:

Photo used with permission – Chase Dekker Wild-Life Images. Read about this Humpback Whale and sea lion encounter at this link.

What about Common Murres?

Upon arrival in Weynton Pass yesterday during one of our regular marine surveys we happened upon a phenomenal amount of bird life. This is not unusual for the area during this time of year. In fact, the abundance of bait fish in the water between August and November often attracts so many birds that even rare species or unusual individuals can be spotted. Such was the case last week when the first record in the country of a blue-footed booby was confirmed in this same spot. Another notable record was this leucistic rhinoceros auklet we photographed a few years back.

Leucistic Rhinoceros Auklet - © JTowers
Leucistic Rhinoceros Auklet – © JTowers

The most abundant species during this time of year however is the common murre. The majority of western Canada’s population of this species (around 3000 pairs) nests on Triangle Island each spring. When it is time for the flightless chicks to fledge in summer they hurl themselves off the cliff and into the sea where they are accompanied by their male parent. The chick is fed at sea for the ensuing weeks as its flight feathers develop and it is during this time that the adults undertake their annual moult. Over time, a significant percentage of the Triangle Island population makes its way about 100 miles south into the protected waters of eastern Queen Charlotte Strait and Weynton Pass where prey such as juvenile herring are abundant.

The common murre colony at Triangle Island - © JTowers
The common murre colony at Triangle Island – © JTowers

During a point count yesterday we observed 1655 common murres within approximately 1 kilometre of our research boat. Over the course of the day we saw several hundred more as well as numerous other bird, mammal and fish species. One thing that most of these species we observed have in common is that they feed on herring and many of them actually rely on common murres and other alcids to corral these fish into tight schools (bait balls) and push them to the surface so that they can be easily fed on. It is thought by some that the reduced wing area of the common murres during the moult may actually reduce drag and increase the maneuverability of these birds while under water catching and corralling everyone’s favourite prey.

Moulting father (with herring in beak) and his flightless chick - ©JTowers
Moulting father (with herring in beak) and his flightless chick – © JTowers

As these birds can not fly, however, they can not go far very fast and subsequently are vulnerable to even the most localized threats such as oiling in contaminant spills and entanglement in commercial salmon fishing nets. Passing Bigg’s killer whales also often take advantage of this vulnerable species during their moult. Juvenile Bigg’s in particular love toying with common murres, unable to fly and therefore unable to escape. Sometimes the birds are left unharmed after several minutes of abuse and other times the birds are drowned or beaten to death before being discarded. While the latter is not likely a significant source of mortality for this species we do intend on keeping tabs on common murre activity in this area in the future. A significant proportion of the province’s population can be found in this small area and many other species here appear to rely on their prey assembling abilities.

Underwing of a common murre chick killed by Bigg's killer whales showing feather development - © JTowers
Underwing of a common murre chick killed by Bigg’s killer whales showing feather development – © JTowers

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~Jared