Hummingbird
Action!
Observations from the Field
(April 19,
2007)
What did eagle-eyed Journey North observers spot this week? Read some highlights and think about the questions that follow!
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Rubythroat: Same Time Each Year! |
Bradyville, Tennessee: I was really disappointed when watching the early migration that my hummers did not come home early. But then the cold weather set in and I was glad they had not. So, I figure my guys are pretty smart because I saw my first one this morning (4/12). It was right on time. They usually show up about now: 2004 was April 10, 2005 was April 10, 2006 was April 9, 2007 was April 12.
Think! Why do you think the observer's first hummer arrives around the same date each year regardless of weather. (Think about what natural change brings on the urge to migrate.)
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Rufous
Hummers:
Following Spring to Alaska |
Auke Bay, Alaska (58.85 north latitude): I have a long time-series of arrival dates for Rufous hummingbird in my yard: 3/31/92, 4/09/93, 4/12/94, (1995: not sure), 4/15/96, 4/11/97, 3/30/98, 4/14/99, 4/06/00, 4/09/01, 4/15/02, 4/11/04, 4/01/04, 4/01/05 4/10/06, 4/13/07.
Think! What was the earliest Rufous arrival date in these 15 years? The latest? Was was the average first arrival date? How can long-term data help scientists who study hummingbird migration?
Pelican, Alaska (58.02 north latitude): First bumble bee yesterday; spring showers with sun breaks in between; record snow levels receding quickly; robins in flocks of 2 dozen; skunk cabbage shoots peeking out. Some blueberry branches are sticking out of snow but most are still buried under snow, quickly melting so berry buds will be numerous soon. Saw 1st flock of swans 2 weeks ago; geese are going north too.
Think! Which of these signs of spring tells you that it's a good time for Rufous hummers to return? For each one, explain your thinking.
Ketchikan, Alaska (55.56 north latitude): Heard my first hummingbird yesterday, and this morning, I saw a Rufous in a blueberry bush, looking for nectar. (The bush is red right now.) He did not find my feeders, which are in the front yard. We did the math from the top of Vancouver Island to Ketchikan, mileage difference, and it was 317 miles. This was on Saturday April 7, so it took 5 days for them to show in my yard. . . . Lots of people around town are seeing them, but not many report on this site!
Think! If the observer saw the same hummingbird that had been in Vancouver Island, how fast would the hummer have traveled per day? Could the observer have known that it was the same hummer? Why or why not?
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