- When Arctic tern chicks hatch the parents will protect them for a few days at the nest site.
- Eventually the chicks will leave the nest site and hide amongst the rocks or vegetation.
- They can recognize the calls of their parents and come forward to accept fish when the parents call.
- Why is this important?
- This helps the chick avoid predation by only coming into the open when a parent has food for it.
These videos are free to use for educational purposes. To download them click on vimeo on the bottom right. To view them full screen click on the symbol next to the HD at the bottom. The bullets can be copied and pasted into a word document.
- When visiting Arctic Tern colonies I have noticed dead chicks laying beside fish that would be much too large for the chicks to swallow.
- Arctic tern parents typically do not break up fish or regurgitate food for the chicks.
- So the size of fish they bring for their chicks is extremely important.
- This video illustrates how this can happen.
- One could speculate that the parent with the fish too large for the chicks had another motive since it ended up eating it.
- Eventually the other parent brings the right size fish for the chick.
- How or why does this sort of thing happen?
- It could be related to the inexperience of the parent. Perhaps this is their or its first time nesting.
- It could also be related to the availability of certain size fish.
- This video shows a couple of ways that American Dippers forage for aquatic insects in streams.
- Sometimes they will swim out over a pool and dive, using their wings, and grab caddisfly larvae at the bottom of the pool.
- Since most of these larvae have cases made out of stones or wood the dipper must get rid of the case.
- You can see how it does this in the video. It grabs the caddisfly by the head and shakes it until the case falls off. Then it eats it.
- Another method of finding aquatic insects is to turn over stones in the stream and grab the insects living under them.
- They also can grasp the substrate with their very strong feet and eat the insects that may be living on top of the stones.
- To learn more about these fascinating birds look at Southeast's Aquatic Songbird (American Dipper) by Bob Armstrong and Marge Hermans
Songbird Feeds Underwater from Bob Armstrong on Vimeo.
- Some gulls, such as this Mew Gull, move their feet rapidly up and down.
- This creates an upwelling which helps bring food from the bottom to the surface where the bird can get it.
- This type of activity is very common in streams where salmon are spawning.
- By doing this the gulls bring salmon eggs laying on the substrate to the surface.
- In this case, however, this gull is standing in an intertidal area.
- This activity brings tiny Macoma clams from the bottom to the water surface where the gull can grab them.
- This video shows the numerous maggots (larvae) from Blow Flies crawling about and feeding on salmon remains.
- A couple of ravens are helping themselves to the nutritious maggots.
- To learn more about these maggots go to the video titled Salmon and Blow Flies in Alaska.
This video helps demonstrate the value of Blow Fly maggots for birds.
Two of these crows are juveniles. So far I have documented 12 different species of birds feeding on these maggots.
Of interest is that almost all of the birds have been recently fledged juveniles.
These maggots are very nutritious and provide these juvenile birds with a good source of food.
Why is this so important?
Most recently fledged birds are fairly inept at obtaining their food.
The slow moving, abundant, nutritious maggots provides an easy to get and important food for these juveniles.
For more information go to the video titled Salmon and Blow Flies in Alaska.
Black Oystercatchers are common nesting birds along most of the southern coastal areas of Alaska.
They usually nest on small islands but in some areas, such as Glacier Bay, they may nest along the rocky mainland shores.
The female typically lays one to three eggs.
This nest has three eggs so the "clutch" is complete.
This video was taken on a hot sunny day in Juneau.
You can notice the adult opening its mouth and panting to help cool down.
Since black feathers tend to absorb rather than reflect the sunlight it is probably too warm.
Both sexes incubate. At first mostly female, but male equalizes duty later in incubation period. Eggs are covered 90–98% of time.
Oystercatchers may select the same nest site several years in a row.
We observed one tagged oystercatcher that nested in the exact same spot for seven years.
- This video shows just a few of the many benefits that Red-breasted Sapsuckers have for other creatures in Alaska.
- Sapsuckers typically drill holes in the bark of trees. Sugary sap wells up in these holes and the sapsuckers lap it up with their brushy tongues.
- This video shows Rufous Hummingbirds, Yellow-rumped Warblers, many insects, and Red Squirrels taking advantage of the sap.
- You will also see some interaction between the parent sapsucker and one of its young. I think it is telling it to go drill your own holes.
- To learn more about these connections open up Natural Connections in Alaska and go to page 50-51.
- This video is an example of the probable play fullness of ravens.
- In this instance the eagle was chewing on a piece of wood.
- The raven harassed the eagle and eventually took it away from it.
- Then it continued to harass the eagle and even pulled its tail.
- To learn more about members of the Corvid family look at Crazy Corvids by Bob Armstrong and Marge Hermans
- Why would the raven take away something from an eagle that was inedible?
- This video demonstrates some of the ways in which marmots play.
- In, at least Southeast Alaska, the Hoary Marmot resides along some of our saltwater beaches and in the alpine.
- Both the beach and alpine marmots play a lot.
- This video was taken along a beach in the Juneau area.
- The group probably involves both parents, one youngster from last year (a teenager) and one first year marmot.
- The one laying down is probably the adult male (dad) because they do not normally take care of the children.
- I suspect the largest one standing is the adult female (mom).
- Marmots are considered "true hibernators" to learn more about them look at Chilling Out How Warm-Blooded Animals Survive Southeast Winters by Bob Armstrong and Marge Hermans
- Then answer the question how does hibernation benefit marmots?
- You can also learn more by looking at Whistlers on the Mountains (marmots) by Bob Armstrong and Marge Hermans