Lat:47.66063861939029, Lon:-122.31028240171611
Day, 2012
4/23/12
1:30-3:30
Today we visited the Burke Museum and looked at the tons of birds they have in collections there. At the Burke, we were led by the museum's ornithology collection manager Rob Faucett on a tour of some of the birds in their collections. Rob taught us a few of the ways they use these collections to study birds. They use plumage patterns to study skin, skeletal specimens to study the size and shape, they spread the wings to study feather pattern and size, and they can also use tissue samples for DNA and other scientific studies. Rob also said that they stuff the birds a certain way so that they lay flat on their backs. Apparently they used to be stuffed so they resembled what they actually looked like living. However, this resulted in a lot of damage when in collections and also decomposition so, even though this newer way doesn't allow you to see the birds' actual shape or wingspan etc., it is still a better method of collecting and storing.
One of the things I thought was really amazing was the molting of different birds' feathers. We looked at two different species: the Black-footed Albatros, and the Canada Goose. With the black-footed albatros, it has evolved to molt its feathers in sections. You can tell by looking at its wings that if 3 feathers are ruff they are older, and if 3 are flat they are newer. They will have three 2 year old feather, three 1 year old feathers, three brand new feather, and then it starts over with three 2 year feathers etc. The albatros has evolved to molt its feathers this way without losing its ability to fly. Rob told us that scientists have experimented or made calculations and apparently, this is the absolute best way possible to molt feathers. To me, that is so amazing.
With the Canada Goose, they fly to near shore islands and molt all their feathers. They've evolved to do this at near shore islands because they can easily feed on the grass and also not have to worry about predators. Seeing as they molt all their feathers, they wouldn't be able to fly away from predators, so molting on an island is the best place for them.
Species List:
Black-footed albatross
Rail
Canada goose
Marbled murrelet
Hermit warbler
Townsend warbler
Lat:47.66063861939029, Lon:-122.31028240171611
Day, 2012
4/23/12
1:30-3:30
Also at the Burke Museum, we learned about Hermit and Townsend warblers. We saw probably about 50 of these small black and yellow birds in the Burke collection. In comparison, Townsend warblers have more yellow on their bodies and look more striped with black, white, and yellow; whereas Hermit warblers have mainly yellow heads with black bodies and white/grey chests. However, as we saw in the collections, there are many hybrid variations of each of these warblers. We looked at many boxes of warblers with Townsends at one end, a whole bunch of hybrids in the middle, and a Hermit at the other end. The hybrids of these birds were very interesting but apparently they aren't seen in field guides so that might get a little confusing.
Interestingly, Townsend warblers are very aggressive towards the Hermit warblers. This forces the Hermit warblers to move southward, away from the Townsends. However, the Townsends eventually catch up and force the Hermits even further south. Subsequently, this also moves the "hybrid zone" in between them south as well. From what Josh explained, this zone moves about 1km south every year. While this "competitive exclusion" is moving the whole warbler system south, climate change is moving it north. Therefore, the whole question with these warblers is what's going to happen when these two forces decrease the size of the hybrid zone or wipe it out all together. I wonder if the Townsend warblers' aggression will reduce the Hermit warbler population or if these Hermit warblers will become extinct as a consequence.
Another very interesting thing about these warblers has to do with their DNA composition. While the DNA between Hermit warblers and Townsend warblers is different, each bird (Townsend or Hermit) can have the DNA of the other. We looked at a map and there were zones with orange and blue dots of varying sizes. The size of the orange dots represented the percentage of Townsend warbler individuals with Townsends DNA; and the size of the blue dots represented the percentage of Hermit warbler individuals with Hermit DNA. This is intriguing because I had never heard of an individual species that can essentially still be that individual while having some of the DNA of another individual.
Species List:
Hermit warbler
Townsend warbler