Videos

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American Dippers will capture and eat young fish in streams. This dipper has captured a chum salmon fry. When dippers feed their chicks salmon fry the chicks have a better survival rate than when they are fed aquatic insects. Why do dipper chicks have a better survival rate when fed salmon young? (Answer: Because salmon fry have a higher amount of protein, calcium and phosphorous than aquatic insects their normal prey.) American Dipper bringing fish to GoPro from Bob Armstrong on Vimeo.

  • When salmon are reasonably abundant and available in streams bears often select the carcasses for certain parts.
  • Sometimes they just bite off the top of the head in order to get the very fat rich brains.
  • At other times they just select female salmon in search of their eggs.
  • Both the fish's brain material and eggs contain more nutrients than just the salmon's flesh.
  • This young black bear is obviously looking for a female chum salmon with eggs.
  • Finally the bear finds one and brings it up on the bank.
  • Notice how the bear just presses on the salmon's belly to extrude the eggs.
  • This would be less trouble than ripping the salmon open to find the eggs.
  • Why do bears sometimes just eat certain parts of a salmon?
  • Answer: The brains have more fat and other nutrients than other parts of the body which is important for the bear to build up fat for hibernation. The eggs also may be more nutritious but in this case this youngster may just like the flavor better.

Black Bear Choosing Female Salmon from Bob Armstrong on Vimeo.

  • Water Bear is a common name for a group of invertebrates called Tardigrades.
  • They are very tiny about the size of a dot made with a pencil.
  • The word Tardigrade means "slow walker" which describes their rather sluggish, clumsy movement.
  • They are one of the hardiest creatures on earth.
  • They have been reported to survive more than 100 years, often completely dried up.
  • They can tolerate extreme below breezing temperatures of minus 200 C.
  • They are even known to survive in outer space.
  • Water Bears are very common in Alaska and 84 species have been found so far.
  • To learn more about them in Alaska look at Tardigrades of Alaska by Carl Johansson etc
  • They are easy to find, see, and study under a microscope.
  • Just grab a chunk of moss, soak it in water overnight, squeeze it, remove the moss and look in the water for them under a microscope.
  • To learn more about these fascinating creatures look at Tardigrades: Bears of the Moss by Miller

Water Bear in Action from Bob Armstrong on Vimeo.

  • Seeds of Sitka spruce are small, averaging 210,000 per pound. Seeds ripen in southeast Alaska during late August or early September, and dispersal usually begins in October.
  • The seeds of Sitka spruce are a favorite food of red squirrels.
  • This video shows a red squirrel extracting and eating the tiny seeds from a Sitka spruce cone.
  • Each seed has an outer covering that the squirrel removes before eating the seed.
  • This squirrel puts the seed with its covering on top of the cone it is holding (actually it is the bottom of the cone)
  • It then extracts the seed from its covering before eating it.
  • Usually a squirrel can extract and eat all the seeds from a spruce cone in around 3.5 minutes. This one took a little longer because it wanted to show us its technique.
  • Why do red squirrels go to all this trouble to extract and eat these tiny seeds?
  • Specific caloric value of spruce seed kernels averages about 27 kJ/g dry weight so I suspect eating a large number of these seeds provides them with sufficient calories.
  • To see what a Sitka spruce seed looks like up close and its size go to photos and in the search box type spruce seeds.

Red Squirrel eating seeds from a spruce cone from Bob Armstrong on Vimeo.

  • Another creature that can live off Sitka spruce seeds is the Red Crossbill.
  • The male has a brick red body and the female is dull olive gray with a yellowish rump
  • Red Crossbills feed mostly on cones attached to the trees, though fallen cones may be important sources of seed.
  • This video shows them feeding on Sitka spruce cone seeds at a Red Squirrel cache.
  • Uses mandibles to bite between cone scales, so that lateral abduction of lower mandible (in the direction of its crossing) opens the cone scale, thereby exposing the seed.
  • Removes seed coat by using tongue to press seed against lateral groove opposite the side of the lower mandible tip; width of this husking groove influences husking efficiency.
  • Swallows small seeds whole, but crushes large seeds in bill before swallowing them, with some loss of pieces, though these may be reclaimed if they fall on branch where bird is foraging.
  • Red Crossbills generally eat up to 2,100 spruce seeds per day.
  • Of interest is these birds may nest almost any time of the year, even in Winter.
  • Why would a bird in Alaska nest in Winter?
  • If the cone crop is good and abundant then they would have enough food to survive and feed their young.

Red Crossbills feeding on spruce seeds from Bob Armstrong on Vimeo.

  • This video shows the actual spawning act of chum salmon and part of the process of excavating the nest and covering the eggs.
  • Salmon nests are typically called redds.
  • The female salmon does all the work of preparing the redd for depositing her eggs.
  • Her goal is to remove enough of the loose gravel so larger rocks with crevices are available to help protect the eggs.
  • Her eggs will sink into these crevices.
  • The dominent male remains close to her and attacks any other males that come too close.
  • He often comes up beside her and quivers his body in hopes of stimulating her to spawn. This video shows him doing this once so watch carefully.
  • When she is ready to spawn she lowers her body over the redd and opens her mouth.
  • The male immediately moves beside her and does the same thing. She releases her eggs and he releases his sperm.
  • Of interest is the subordinate male or males move up at the same time and release their sperm.
  • They can do this because the dominant male is concentrating on releasing his sperm.
  • Immediately after laying a portion of her eggs she moves ahead of the redd and begins moving gravel over the redd site.
  • Her first few digs, however, usually do not move any gravel but drive the eggs into the spaces between the gravel.
  • You will notice a Dolly Varden (the bright fish with light spots) enters the nest site in hopes of finding an egg to eat. In this case I think the female chum salmon was successfull in covering the eggs.
  • Salmon usually only deposite a portion of their eggs in one nest. The female will typically move ahead of the nest she spawned in and begin digging another nest. Usually the gravel she covers her nest with is the beginning of excavating another nest.
  • Female chum salmon typically build four to six redds in succession in one place.
  • When all of her eggs are buried she stays in the area and defends the nests until death. The male then will go off and look for another female.
  • Why don't salmon deposite all of their eggs in just one nest?
  • By having multiple nests it helps increase the chance that some eggs will survive to spring when the fry emerge.

Chum Salmon Spawning from Bob Armstrong on Vimeo.

  • These Sitka black-tailed Deer twin fawns were just born and the mother (doe) is starting to take care of them by nursing them and licking.
  • At this stage the fawns have some difficulty walking and standing -- note the one that falls down.
  • Fawns usually weigh 6.0 to 8.8 lbs and have no scent for the first week or so.
  • Having no scent means that predators would have difficulty finding the fawns.
  • This enables the mother to leave the fawn hidden while she goes off to browse and replenish her body after giving birth.
  • Notice that the doe spends some time licking the rear end of the fawns.
  • Why does she do this?
  • The reason the Doe is licking the Fawn's rear end is to stimulate a bowel movement, which in turn will help keep the Fawn's odors in check while it is bedded down in a safe location.

Sitka black-tailed Deer Nursing Twin Fawns from Bob Armstrong on Vimeo.

Ravens Eating Blow Fly Maggots from Bob Armstrong on Vimeo.

  • When bears drag salmon out of the stream blow flies usually lay their eggs on them.
  • In a few days the eggs hatch and huge numbers of the larvae, called maggots, feed on the salmon carcass.
  • These ravens are taking advantage of this and eating the very nutritious maggots.
  • To learn more about this process go to the videos titled Salmon and Blow Flies or Salmon and Blow Flies in Alaska.

Red-breasted Sapsucker Benefits Rufous Hummingbird from Bob Armstrong on Vimeo.

  • This video is a good example of the relationship between Red-breasted Sapsuckers and Rufous Hummingbirds.
  • Sapsuckers typically drill holes in trees which causes the tree to release some of its sap.
  • These woodpeckers have a brush-like tongue to lap up the sap. Other woodpeckers have a tongue with a sharp, horny tip for spearing insects.
  • To learn more about woodpeckers go to Drummers in the Woods (Woodpeckers) by Bob Armstrong and Marge Hermans
  • To learn more about Rufous Hummingbirds go to To Mexico and Back Again (Rufous Hummingbirds) by Bob Armstrong and Marge Hermans
  • This sapsucker has gathered insects and sap to feed its youngsters.
  • In Alaska Rufous Hummingbirds are known to nest near sapsucker trees and feed heavily on the sap -- which may be more nutritious than flower nectar.
  • The hummingbirds will feed their youngsters the sap and the insects that might be attracted to the sap.
  • The distribution of Red-breasted Sapsuckers and Rufous Hummingbirds in Alaska is nearly identical.
  • Why?

Pacific Herring Spawning and Great Blue Heron Takes Advantage of It! from Bob Armstrong on Vimeo.

  • These Pacific herring females were laying their eggs on mussels in Auke Bay, Juneau Alaska.
  • Of interest is there did not seem to be any males taking part.
  • This Great Blue Heron spotted the activity from about 200 feet away and flew nearby.
  • It started eating the herring which appeared to be fairly easy to catch.
  • Great Blue Herons are fascinating birds. To learn more about them look at Things that go Squawk in the Night (Great Blue Herons) by Bob Armstrong and Marge Hermans

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