In mid-afternoon today (3/28/2010) I observed a crow chasing a much smaller bird. The chase started somewhere near one of the bird feeders in the front yard and continued up to a mid-height level in the fir trees. The potential victim eventually escaped the crow. The bird that was being chased flew in a curious spiraling pattern, and the possible reason why escaped me at the time. But as I thought about it more I came up with a theory.
First, it’s fairly unusual to see a crow chase another bird unless it is either very young, is sick or disabled or otherwise can’t defend itself. It’s probably too early in the breeding season to have fully-fledged young around. I think the bird being chased may have been a House finch and that the finch may have had the disease that forms tumors on its face. That disease is rife amoung the House finch population and was evident where we lived in Texas back during at least the 1990s. The tumors will eventually result in the bird’s death, either by deforming the beak so that it starves to death or by blinding it with the same result. I think this bird may have been blinded in one eye and that’s why it was flying in the spiraling pattern… it was the only way it could see where it was going.
It’s just a theory but I suspect it’s a good one.
The House finch tumor disease is one of the reasons that you are admonished to clean your feeders regularly. While I'm certainly not an opponent of regular feeder cleaning, I've observed that the finches with the tumors are more dependent on the feeders than other birds. They're often too sick or blind to obtain food from any other sources. If you try to chase them away from a feeder they often won't fly far since they're already sick and/or partially blind. So that sick finch can and probably will be quickly back to a feeder you have just cleaned.
If the bird is allowed to hang around it will only die a slow and painful death and the longer it is in the area the greater the chances that it will transmit the disease to the other finches.
Sunday, March 28, 2010
Wednesday, March 24, 2010
Hummingbirds and Memory
March is the month for welcoming our Rufous hummingbirds back to Anacortes. I saw our first one here on March 14, the day we returned from a ten-day trip to Baja California. I usually try to keep this blog focused on Pacific Northwest birding but you will need to bear with me a little on this posting.
My wife and I moved to the PacNW in 2001 after living in the same house in Austin, TX for about ten years. We were fortunate enough to be able to live relatively near downtown but have a wonderful greenbelt with a creek along the back of the house and a large vacant lot immediately adjacent. While the location was wonderful we were somewhat stymied by all of our shade (large pecan trees) and were unable to grow flowers in the yard, which would have helped us attract hummingbirds. I tried for several years to attract the predominant Black-chinned hummingbird to feeders at the house in the spring or summer but was never successful although they are abundant in the general Austin area. The Black-chinned hummingbirds not only migrated through our area, but they also bred in our area. But I was simply unable to attract the birds to a feeder in the spring or summer and finally gave up trying.
Fall was another matter. I noticed that we had some migrants that would pass through in early September, so I began putting one or two feeders out in the fall. My computer allows me a little more sophisticated reminder of when to put the feeders out now, but back then my stimulus was the appearance of the first hummingbird in the fall.
Every fall, without fail, one or more hummingbirds would appear at the same place the feeders had been the previous year and begin to look for the feeder. They would fly to the exact spot where the feeder had been in the front yard or above the rear deck and do a slow turn looking for the feeders that had been in those locations! That was my cue to perform a crash production of sugar-water and get a feeder out… pronto! There was no way to tell whether I was attracting a couple of hummingbirds or several hummingbirds but they would frequent the feeders for about three weeks before continuing on their migration.
Since we didn’t keep feeders out in the spring or summer, and kept them out for only about three weeks in the fall, these Black-chinned hummingbirds had to remember for an entire year the previous location of our hummingbird feeders and that they were only available for the fall portion of their migration! We never observed either the hummingbirds or this behavior in the spring. And ours was only one stop for a bird that migrates hundreds of miles each year lending me to believe that our location probably wasn’t the only one they held in memory.
Back to the PacNW. This past week I noticed one of our returning Rufous hummingbirds (our predominant species which breeds here during the spring and early summer) return to the wire hanging from our Pacific yew tree where I had hung a feeder last year. It was obviously looking for the feeder that had been hung there last season. We’re not discussing only locating a yard, but the exact location of last year’s feeder! It wasn’t there… I had moved it to another limb at a location about ten feet away. The hummingbird quickly found the feeder’s new location, but the point is that a second species of hummingbird obviously remembered the exact location of the feeder from the previous year! In this case this could have been a bird that had bred here and therefore had several months to imprint the feeder’s exact location, but still at least seven months had passed with two migrations of several hundred miles each prior to the bird returning to the exact location of the feeder.
My wife and I moved to the PacNW in 2001 after living in the same house in Austin, TX for about ten years. We were fortunate enough to be able to live relatively near downtown but have a wonderful greenbelt with a creek along the back of the house and a large vacant lot immediately adjacent. While the location was wonderful we were somewhat stymied by all of our shade (large pecan trees) and were unable to grow flowers in the yard, which would have helped us attract hummingbirds. I tried for several years to attract the predominant Black-chinned hummingbird to feeders at the house in the spring or summer but was never successful although they are abundant in the general Austin area. The Black-chinned hummingbirds not only migrated through our area, but they also bred in our area. But I was simply unable to attract the birds to a feeder in the spring or summer and finally gave up trying.
Fall was another matter. I noticed that we had some migrants that would pass through in early September, so I began putting one or two feeders out in the fall. My computer allows me a little more sophisticated reminder of when to put the feeders out now, but back then my stimulus was the appearance of the first hummingbird in the fall.
Every fall, without fail, one or more hummingbirds would appear at the same place the feeders had been the previous year and begin to look for the feeder. They would fly to the exact spot where the feeder had been in the front yard or above the rear deck and do a slow turn looking for the feeders that had been in those locations! That was my cue to perform a crash production of sugar-water and get a feeder out… pronto! There was no way to tell whether I was attracting a couple of hummingbirds or several hummingbirds but they would frequent the feeders for about three weeks before continuing on their migration.
Since we didn’t keep feeders out in the spring or summer, and kept them out for only about three weeks in the fall, these Black-chinned hummingbirds had to remember for an entire year the previous location of our hummingbird feeders and that they were only available for the fall portion of their migration! We never observed either the hummingbirds or this behavior in the spring. And ours was only one stop for a bird that migrates hundreds of miles each year lending me to believe that our location probably wasn’t the only one they held in memory.
Back to the PacNW. This past week I noticed one of our returning Rufous hummingbirds (our predominant species which breeds here during the spring and early summer) return to the wire hanging from our Pacific yew tree where I had hung a feeder last year. It was obviously looking for the feeder that had been hung there last season. We’re not discussing only locating a yard, but the exact location of last year’s feeder! It wasn’t there… I had moved it to another limb at a location about ten feet away. The hummingbird quickly found the feeder’s new location, but the point is that a second species of hummingbird obviously remembered the exact location of the feeder from the previous year! In this case this could have been a bird that had bred here and therefore had several months to imprint the feeder’s exact location, but still at least seven months had passed with two migrations of several hundred miles each prior to the bird returning to the exact location of the feeder.
Friday, March 19, 2010
Denizens of the Brush Pile
We returned from a Lindblad cruise to Baja California Sunday (3/14) and within a couple of hours I had observed a male Rufous hummingbird visiting our feeder that we maintained over the winter for Anna’s hummingbirds. This was our first Rufous of the season although it's possible we had this or others visit earlier while we were away. Also back this week were a Brown creeper (a not unusual but erratic visitor), a Bald eagle being harassed by crows, a Varied thrush and a male Northern flicker (a usually consistent visitor but less common for the past couple of months). Early this morning while working on the computer a faint sound in the background caught my attention and I opened my window to hear a Barred owl calling in the distance... a very rare treat.
We had a day of full sunshine so late this afternoon I took my camera out to the brush pile in our front yard and scattered some seed on the ground. I haven’t been out in quite a while so the birds are shy, but lurking around in the brush pile were two Spotted towhees, two Golden-crowned sparrows (which will soon be leaving for their breeding season elsewhere) and the ever-present Song sparrow. Although in decline due to the upcoming breeding season, we still have a healthy supply of Dark-eyed juncos (Oregon race). They’ll be leaving soon for higher ground but will be evident at higher elevations such as Washington Park and Mount Erie.
(4:35pm) Bulletin!
Just as I removed my camera media card to download photos for this posting I saw a large bird fly down into or onto the brush pile. I grabbed my binoculars and searched the pile to no avail, but a couple walking a dog soon flushed an accipiter from the brush pile. I reloaded my camera and went outside to get a photo, but the bird flushed, landing in two different fir trees in the front yard before finally flying off to the north. I did get two photos but I already have much better photos posted in prior blogs so I won’t post the accipiter photos. I appreciate it a lot more if it would help clean out last year’s crop of House sparrows but I’m sure it’s not that selective and would just as soon dine on some of the aforementioned birds!
We had a day of full sunshine so late this afternoon I took my camera out to the brush pile in our front yard and scattered some seed on the ground. I haven’t been out in quite a while so the birds are shy, but lurking around in the brush pile were two Spotted towhees, two Golden-crowned sparrows (which will soon be leaving for their breeding season elsewhere) and the ever-present Song sparrow. Although in decline due to the upcoming breeding season, we still have a healthy supply of Dark-eyed juncos (Oregon race). They’ll be leaving soon for higher ground but will be evident at higher elevations such as Washington Park and Mount Erie.
(4:35pm) Bulletin!
Just as I removed my camera media card to download photos for this posting I saw a large bird fly down into or onto the brush pile. I grabbed my binoculars and searched the pile to no avail, but a couple walking a dog soon flushed an accipiter from the brush pile. I reloaded my camera and went outside to get a photo, but the bird flushed, landing in two different fir trees in the front yard before finally flying off to the north. I did get two photos but I already have much better photos posted in prior blogs so I won’t post the accipiter photos. I appreciate it a lot more if it would help clean out last year’s crop of House sparrows but I’m sure it’s not that selective and would just as soon dine on some of the aforementioned birds!
Spotted towhee
Song sparrow
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