Phantom Feeder with slight move.

We noted in an earlier post that moving a feeder 18" caused birds to fly to the former location for several attempts. We have noted now, that moving it only a foot will do the same thing. Removing it (as we sometimes do to discourage squirrels) also creates the same effect.

Theory on how Hummingbirds make it across the Gulf

Hummingbirds fly to and from Central America. They do build up fat for the trip, but the amount hardly seems to be enough for them to make it. http://news.bbc.co.uk/earth/hi/earth_news/newsid_8149000/8149714.stm an observation that dragonflies make a similar journey in the Indian ocean of 500-1200 kilometers suggests two theories.

The dragon flies use wind currents, so that is one solution. Birds follow them and eat them as they go.

So a second theory is that there is some as yet unkown insect which makes a journey over the gulf at about the time of hummingbird migration, thus supplying them with sustenance while on their trip. There are some islands along the way, but they don't have a huge influx of hummingbirds during the time of the trip. But they might serve as bases for insects which the hummingbirds might eat on the fly.

Do Cardinals use their songs for echolocation?

I've noticed for years that cardinals have a constant tweeting sound when on the ground and often on a perch. I've even seen a female or male sitting on a fence tweeting while the other ate at a feeder. The whole concept of making all this noise on the ground struck me as counterintuitive for survival purposes. One would think that the noise would attract predators.

Then recently I read an article in New Scientists ( http://www.newscientist.com/article/mg20227031.400-echo-vision-the-man-who-sees-with-sound.html ) about a man who could navigate using clicking noises. This was not unique to him. He could also teach others. A salient point in the article was how detailed his perception could be. He and his students could detect sidewalks vs lawns, fences vs hedges, and various sizes of bowls. Higher pitches allow more detailed detection at the price of only detecting things that are near.

It occurred to me that the cardinal's incessant tweeting would be helpful for survival if they used it for echolocation and to detect predators without necessarily seeing them. The perception would not have to be detailed since any change in environment would signify potential danger.

They may also use it for echolocation while flying. I've noted that cardinals are the last birds to go home to nest in the evening. They are the last birds to leave our feeder at twilight.

None of this is proof that cardinals use their tweeting for the purposes mentioned, but it does suggest an area for research.

Ruby-Throated-Hummingbird aggression and territoriality

The first year we watched Ruby-throated-hummingbirds (Ruby, Rubies) we got a late start in the season. We noticed that one Ruby would attempt to take over our feeder and drive off all others. Usually this was a Ruby male and usually the male dominated the feeder until late in the season. At this time, a female drove off the Ruby male and then she dominated the feeder.

At this time we thought that all Ruby hummingbirds were so territorial that only one bird would come to our feeder at a time. Watching Youtube.com videos of dozens of hummingbirds surrounding a feeder made us envious.

And there the issue rested until a year ago. I was visting a marina in Eastern North Carolina in early June which had a hummingbird feeder. About a half dozen birds surrounded the feeder and more or less shared it with only a little nudging back and forth. I presumed these must be some sort of different hummingbirds as all the rubies I had ever seen would never have allowed this to happen.

A year later in Winston Salem, we set up a feeder much earlier. We had seen an occasional bird as early as late April and we didn't want to miss the opportunity to feed them on their way north. Although a few would inspect our feeder, during the month of may, none stopped. Then in early June, ruby throated hummingbirds began to arrive and feed at our feeder. At first it was only one, then we noticed that there were at least three different birds feeding at our station. All were females and while none fed at the same time, there was no interference by another in terms of using the feeder. It was a serial sharing relationship. This isn't much of a relationship, but it is at least friendlier than the hostile we had observed a couple of years before. This lasted for about a month. Not only did they feed at the syrup feeder, they would land in a nearby fruit tree and catch fruit flies.

Then in mid-July, males began arriving and it wasn't too long until a ruby male began chasing off other rubies as they tried to feed. He chased off males and females alike. It occurred to me, then, that the birds I had witnessed in Eastern North Carolina were indeed female Rubies and the reason for their cooperative feeding was twofold: (1) it is likely they were just arriving from a long migration from Central America and needed to replenish their fat stores. Hense, as long as the feeder was available most of the time, they weren't in a position to fight off other birds. The need to eat exceeded the need to dominate the feeder. (2) Females might be less agressive and territorial than males (although late in the season in the first year they had demonstrated a willingness and ability to be so).

It is now early August and I expect the male who has 'captured' our feeder to continue to dominate it for the month. But I predict a larger female will drive him off late in August or early September. That strategy makes sense. She, after all, needs to build up body weight for the flight back to Central America. What doesn't make sense is why the male chooses to dominate the feeder against all--including females.

Perhaps some clever person will explain that.

Wren uses Plastic to build nest

This year we built a birdhouse out of a flowerpot and placed it on a fence in our courtyard. It was ultimately occupied by a wren. The wren built its nest and raised its brood before abandoning it several weeks later.
Out of curiosity as to how a wren builds its nest, I opened up the pot and carefully removed the nest. I observed something milky and translucent in the bottom of the cup of nest and thought it might be albumen. After carefully dissecting the nest, I realized that the translucent material was plastic. Some of it was from food wrap and was crisp similar to cellophane. Other pieces were softer and in the polyethylene category similar to the plastic used by dry cleaners or on produce bags in grocery stores. One piece still had printing on it. Most of the pieces were roundish and about the size of a quarter or half dollar. There was one strand of rigid plastic similar to that used in electric ties that had been woven into the structure of the nest in much the same manner as the long pine needles and sticks had been used. However, the sheet plastic was positioned in overlapping layers at the very bottom of the cup of the nest where the eggs would have been. Under this was very fine material...possibly squirrel or cat fur, down, or finely shredded wood.
The placement of the plastic sheets appeared to be deliberate to accomplish some specific purpose. I drew this conclusion because it was carefully structured at the bottom of the nest and no place else. It did not appear any place except at the bottom of the next cup. It was not interwoven into any other place in the nest structure nor tdid it appear higher in the cup. Also, the size and shape of the plastic suggested that it had been cut by the bird as opposed to having just been found.
Do you have any ideas as to what was on the wren's mind when she built her nest that way? Was she applying a common technique that she might have used with some natural material or was she adapting a strange new building material in some novel way.

Finches Fighting

House finches are usually social birds. By this, I mean that they frequently arrive at a feeding station together, leave together, and that they allow each other's presence more or less. They even intermingle with gold finches which are somewhat smaller.

The civility comes close to that of a bunch of kindergarten children in that they eat as a group, but there is some nudging and shoving. This is easier to observe at cylindrical feeders with multiple holes than at dishes. It isn't unusual that one will land on another to chase it away from a feeding hole. Typically this works and the attacker gets the feeding hole. The other flies up to a nearby roosting point, checks out other places on the feeder and then goes to one of those that is free.

However, lately, we have observed several fights among the finches. While I can't be absolutely certain, it appears to mostly occur between male house finches.

Whether at the feeder or the dish, they will all seem to be peacefully eating until suddenly, two finches will rise straight up several feet in the air, facing each other and flapping their wings. It appears to be an aerial shoving match since neither bird seems to make forward progress and both birds seem to be in each other's face.

The process is quick, explosive, and unpredictable. Weeks can go by without any fights and then several appear in a day. It's difficult to videotape these experiences because of the unpredicabilityl The fight seems to be over when one or both birds turn away to land. I suppose the winner is the one that returns to the feeder fastest.

I wonder why this kind of activity appears in bursts. I have a suspicion that it is juveniles, but that is harder to tell with finches than some of the other birds.

Do Cardinals dare each other?

This article doesn't have a neat conclusion. I've been observing birds in our yard lately (Early September, 2006).

I noticed that two cardinals who seemed to be "daring" each other to engage in "dangerous" behavior. The first cardinal was a juvenile and the second appeared to be a young adult (as judged by the color of their beaks).

First the juvenile cardinal landed in the dish and just sat there seemingly to wait for the Dove to do something. When the dove continued to eat peacefully, the juvenile cardinal took two or three pecks at the sunflower seed and then flew off. A second cardinal arrived almost immediately. It too waited a moment or two (but less time than the first) and then it took one peck at the seeds and flew off

It doesn't sound like very strange behavior unless you consider what Cardinals typically do.

Cardinals don't typically like to share the food dish with other birds—particularly larger ones. (They will occasionally tolerate finches). As it happens, doves are usually peaceful. However, Doves are large for backyard birds and the mere act of raising a wing will scare off most birds and animals. Raising the wing makes the Dove look large and the down stroke of a dove wing carries quite a bit of force. Squirrels even avoid doves unless they are really hungry. (Oddly, house finches will routinely join doves). There isn't much space left after an adult dove gets in the feed dish, so cardinals avoid them. So the first thing that made the above observation strange was the mere act a cardinal of landing in the dish with the dove. The fact that two did it in quick succession was more than doubly unusual.

Cardinals usually take quite a while eating in a sunflower dish. Some birds (Chickadees and Blue Jays for example) will come to the dish, grab a seed or two and then go off to eat elsewhere. That's because these birds have to exert quite an effort to crack the seed in order to eat the heart. But Cardinals can easily crack the seed in their mouths. When Cardinals encounter sunflower seed, they frequently will sit and gorge until they are full or until something comes along to frighten them. Taking only one or two bites is unusual for cardinals. The fact that the two birds did this in quick succession was also unusual.

It is not unusual for juvenile cardinals to engage in intimidation battles. They not only do it with others of their species, but at least on one occasion I observed a juvenile successfully face down a timid Jay. (Only to be scared off by a larger more intimidating Jay). At the time, I took this to be the foolishness of youth, but perhaps juvenile cardinals must 'show their courage" some how. If so, it would surprise me, because cardinals don't appear to be that socially conscious Perhaps it is some sort of pre-mating demonstration.

But as I said, don't have a neat conclusion on this one.

The Attack of the Killer Peanuts

As mentioned in The Attack of the Killer Peanuts

As mentioned in Adventures in Bird Feeding, we have a basket nailed to the top of our courtyard fence so that we can feed blue jays sunflower seed. Occasionally, we also placed peanuts on the ground for them to eat. This is about a time we changed things a little and dropped the peanuts into the basket.

Blue Jays love sunflower seed. They like them whole. They like them even more if they shelled into just the hearts. They will stand around and stuff their craws with the seed before leaving. While whole sunflower seed is a wonderful fat rich food providing enormous amounts of energy and nutrition, it does have some problems. Jays eat just the hearts. To eat the heart of a whole sunflower seed, they must take one seed, fly to a nearby tree, place it between their toes, and peck at it until it cracks enough for them to harvest the nutritious heart. As large as Jays are, this is apparently the most efficient technique they have to eat whole sunflower seeds. But it is extremely slow.

In case you are unaware, many small and medium sized birds also like whole sunflower seeds. Cardinals, for example, seek them out also. But the process is simpler for a cardinal. A cardinal takes the seed into its mouth and crushes it enough for to extract the heart. In the process, the husks fall out of either side of its mouth. (I would love some really close up photography of exactly how cardinals do all of this.) Unlike jays, Cardinals can easily process and eat a great quantity of seed in a small amount of time. So the seeds are a more more efficient source of food value for them than for jays.

Chickadees love sunflower seed, too. Chickadees (10-11 grams) are tiny birds, are a fraction (1/8th) the weight of a Jay (70-100 grams). They use the same technique of seed between the toes to extract the sunflower heart and they are about as fast at it as well. So relative to their food needs, whole sunflower seeds are an efficient source of food for them also.

It very logical then that blue jays love peanuts even more than they love sunflower seed—especially in the shell. Peanuts are much easier to open and the food value is significantly greater than a sunflower seed. This is especially true when the shell contains two or more peanuts. The shell acts as a container allowing the jay to bring in a really huge haul to the family. I can just imagine all the praise daddy blue jay gets when he brings two nuts in the shell to mom and the nestlings. (I have seen jays actually haul off two peanuts at a time: one used the strategy of two in the beak while another stuffed one in its craw and carried the other in its beak.)

When there is a large source of peanuts in a comfortably safe location, blue jays will shop the array of available nuts before choosing just the right one. They will first pick up one and the drop it when they see another that might be more desirable. They may pick up and drop two or three peanuts before making a final decision. Sometimes they select their third choice, sometimes the second, and sometimes they will return to their first choice. Whatever their criteria, they can tell more about the nut when they pick it up than they can by simply looking at it. The whole process reminds me of women shopping for cantaloupes in the produce department by picking them up and smelling them.

As I mentioned earlier, we had placed a basket for the blue jays to eat sunflower seed so that they wouldn't bother our other feeders. Anytime we let the seed supply get low, they would sit on the basket, look at us, and make various blue jay noises ranging from screeches to bell tones. In fact, when the supply got low, they actually seemed mad at us.
I recall when I first experienced this I wondered, "Where in their natural lives do they learn that making a fuss will get them what they want?" (I got a clue when I saw bird parents feeding fussy juveniles.)

The basket on the top of the fence actually worked so well, that the blue jays became reluctant to enter the court yard to get peanuts from the ground. I'm not sure why. Perhaps they got used to the safety of the high-off-the-ground food source. Or perhaps they had a meeting and decided we might get mad at them if they came in the courtyard. But whatever reason, when we occasionally placed peanuts on the ground within easy sight of the blue jays, they still were reluctant to drop to the ground to get the nuts.

So one day, I gave in and placed three or four peanuts in their sunflower seed basket.

As it happens, most birds do not usually fly in from a distance and land on a food source. Even with the basket high on the fence, they typically either land on a tree nearby or elsewhere on the fence. They check it out. They size up the safety. If another bird is in the basket, they make a determination of whether it will be intimidated by them or not. In the case of other species, smaller birds will usually yield right of way. Within the blue jay family, there is an obvious hierarchy. The more timid blue jays will wait out another and then hop in the basket. The more aggressive will drop down on the timid one who hops out of the way and waits for the other to finish before returning.

Knowing all of this on the day I dropped peanuts into the basket for the first time, I wasn't expecting anything unusual. The blue jays liked sunflower seed. They liked peanuts more. They liked the basket as a food source better than they liked the ground. So, I figured, it's just logical they would really love peanuts in the basket.

It wasn't too long before a blue jay showed up. It landed in the nearby tree, hopped around looking at the courtyard and then dropped to the basket on the fence. It was only within inches of the basket, when it became alarmed, flapped its wings wildly, raised itself four feet over the basket, and then dropped several feet away on the fence. It flew back to the tree and looked down. Then it flew back to the fence several feet away. In a sort of choppy walk, it sidled over to the basket with its neck outstretched and timidly glanced sideways into the basket. It looked like Charlie Chaplin without the cane. After it glanced, it ducked a moment to decide on what it had seen. After doing this several times, it finally decided that the basket was safe and those things in the basket were the familiar food favorites, peanuts. Or so it seemed, because the blue jay hopped up on the basket, chose a peanut and headed back to its nest.

It returned later and confidently went through its usual procedure of simply dropping to the basket knowing that it would see peanuts in the basket. But other blue jays which had not been alerted went through the entire procedure that the first one had of jumping up and then re-inspecting the basket until deciding (usually) that it was safe to land in the basket. (A few decided not to wait around to find out if it was dangerous and simply flew off.)

We thought that it was very funny that the birds showed such a fear reaction to the peanuts and we laughingly labeled this feeding adventure "The Attack of the Killer Peanuts." We presumed they might not be able to identify the unfamiliar shape at first and probably thought they were snakes or something. We decided our jays just might be a bunch of chickens.

We ran out of peanuts. Several months passed. We just feed sunflower seeds. Things settled in with the jays.

One day during the winter, I thought I would provide the jays with an extra treat. I still didn't gave peanuts so I put sunflower seed hearts in the basket on top of the regular whole sunflower seeds. As I mentioned, blue jays love sunflower seed hearts. They are rich source of food value and the jays don't have to go through the effort of shelling them. Once again, I thought this would be an unqualified delight to the Jays. And once again, I was wrong. When they dropped to the basket of hearts sitting in the middle of regular whole sunflower seeds, they went through the same alarm and discovery process they had for the peanuts. Several also flew off without further investigation.

This had me scratching my head in bewilderment. I could imagine that peanuts might look vaguely like something dangerous, but I couldn't see how the sunflower hearts would.

One more event finally helped me solve the puzzle. After several hours, I decided that since the sunflower hearts had scared the blue jays, I would remove them and go back to just plain sunflower seeds. Blue jays which had already been through the discovery process returned and they treated the absence of sunflower hearts the same way they had treated their appearance: with the alarm and investigate procedure. A day later, I emptied the entire basket and the birds reacted to the empty basket the same way.

Speculation:

I was slow, but I finally understood. It didn't matter what was in the basket. What mattered was whether the basket contents looked the same as the last time the jay had visited the basket. So it wasn't the contents. It was the change that bothered them. And it didn't matter what the change was. Whether it was something that had formerly been familiar with or whether it was something totally strange, the birds were not going to take chances and land in the basket without investigation if it didn't look like it did the last time they were there.

Just as in the case of the phantom feeder, I concluded that the birds carried a map of expectations in their minds. In this case, it was a picture of what they expected the basket to contain. When observation didn't correspond with that map, they would have treat it as dangerous and re-examine the situation. Once again, I am lead to conclude that the birds must have a prodigious memory for the details of their world.

Also, similar to the conclusion of the phantom feeder, I realized that birds don't actually see where they are landing until the last moment. The jays didn't become alarmed until their feet almost touched the basket.

Adventures in Bird Feeding

When we first started feeding birds last year, we had a small plastic feeder which we hung from a fruit tree and a large plastic dish which we placed on the ground. The small feeder quickly fell apart, but the dish served as a solid place to attract many types of birds: cardinals, sparrows and blue jays were particularly fond of the dish on the ground. But regrettably, so were squirrels and chipmunks.

You would think that chipmunks are such tiny creatures that they couldn't be very much of a problem….you would think that, but you would be wrong. Those cute pudgy cheeks shown in cartoons really exist. They really do bulge out –but only when they are packed with food that the chipmunk carries quickly back to a burrow somewhere for use later. And in just a few moments, they are back harvesting food for another mouth bulging trip home. So actually, though really tiny, chipmunks can vacuum up vast quantities of bird seed very rapidly—far more rapidly than squirrels and certainly more than any of the local birds. The chipmunks are relentless. Since they really aren't eating much or at all, they never get full. They continued to remove all the bird feed we put in the dish on the ground until it is gone. They can usually empty the dish in an hour.

Other animals don't think chipmunks are cute. Indeed, on the ground, most other birds and animals are afraid of them at least to some extent. This might seem reasonable for a sparrow, because the chipmunk is bigger and has the extra advantage of being a land animal in its favored habitat. But a blue jay is many times the size of a chipmunk but yet blue jays are afraid of chipmunks also. When a chipmunk is feeding from the dish on the ground, it will rush blue jays scaring them. Depending on the Blue Jay, it will fly off to some other place to eat or simply jump back a foot or two and wait out the chipmunk. If the blue jay is there first, it will sidle to the side of the dish and start eating. Then it will forget that it was the second one there and rush the blue jay anyway.

The squirrels we have observed won't try to compete with chipmunks on the ground, either. When a squirrel finds itself on the ground near a chipmunk, it creates some distance and will give up the food dish if necessary to maintain that distance. And when a chipmunk knows there food to be gathered, it is always necessary to maintain distance. It will rush the squirrel if necessary to get it to move out of the dish or even to move a greater distance away.

Chipmunks aren't even friendly and sharing with other chipmunks. In fact, they are more violent with other chipmunks than they are with birds and squirrels. Birds and Squirrels just get intimidated to move a few inches or feet away. But other chipmunks get much more violent treatment. One chipmunk will try to claim the entire courtyard area and will attack any other chipmunk that comes within sight of it. High-speed chases with lots of squeaking protests and perhaps some bites are a regular event during the day. The other chipmunk must either leave the court yard or at least find a hiding place where the other one can't find it. It's an effective strategy for the dominant one but only for a while. Usually two or three other chipmunks will be waiting just out of sight. Sometimes it will be behind the air conditioner. At other times they jump into a tall flower pot and duck down. Sometimes they become lost in the bushes. A few will simply stop just outside the fence. They will all wait until the dominant goes back to its burrow with its cheeks full. Then the next bravest one cautiously heads for the dish and the others spread out to gather anything else that might be scattered on the ground within the area normally defended by the now absent dominant chipmunk.

So we set out to solve the chipmunk problem. First we bought a metal shepherds hook style post with four hanging arms and a set of four different types of cylindrical feeders with perches or wire feeders. We continued with the dish on the ground, but we didn't put as much feed in it. Eventually, we just placed it under the cylinder feeders and it caught some of what the birds dropped which the chipmunks would clean up.

This eliminated the chipmunk problem. They were now doing us a favor by cleaning up the feed that the birds dropped. But squirrels started jumping to the feeders from a nearby fence. This caused us to move the feeders a little further from the fence (which created the inadvertent experiment in The Phantom Feeder). The squirrels could no longer jump from the fence or any other object to the top of the feeder, but they amazed us when we discovered them climbing the half inch square smooth metal post to the shepherd hooks, sliding and crawling their way over to the feed cylinders and then using their front feet they tiled the feeders dumping the food into their mouth (and even more on to the ground) while hanging on with their two rear feet.

Frankly, we admired their acrobatic skill and clever ingenuity. We watched them in awe for several days. We would chase them off at the times birds normally eat and this would allow us to watch the birds. The squirrels developed all kinds of clever ways to dump the feed from the feeders to the ground during the night. Then they would eat at night and the chipmunks would clean up what they missed during the day. It wasn't perfect, but it was workable.

I hit upon the idea of putting petroleum jelly (Vaseline) on the post and the shepherd's hooks. This worked pretty well and we had great fun watching them jump on the pole, then slide down it (in the middle of summer). They couldn't get a good enough grip to climb the pole and they got too much grease on their paws to hang on to the bottom of the cylinders even when they could get to them. After they tried for several days, they eventually became discouraged and only occasionally would try again just in case the pole ceased to be slippery.

Vaseline was a nuisance for the birds because they often landed on the shepherd's hooks before selecting a feeder. If they landed on a part with too much slope, they would end up sliding to the bottom of the hook. They would just have to hop to a feeder a little faster, so we lived with that problem—or rather the birds did.

At this point the squirrels were now minor pests though they still struggled to find some weakness in our defense. However, now we noticed that blue jays weren't the most desirable bird to have at the feeders. When they were there, anything smaller wouldn't come to the feeders. That turns out to be every other type of bird that was visiting our feeders.

It occurred to me that blue jays needed to eat too, and they are really fun to watch. So I nailed a breadbasket to the top of our courtyard fence and put whole sunflower seed in it. I hoped to train them to stay away from the feeders and just use the basket. And it worked! I would watch during the day. Because the feeders were only a couple of meters away from me, they wouldn't come to the feeder. Smaller birds would. Since I provided the blue jays with their favorite food in the basket, they quickly learned to go there and eventually, they forgot all about the feeders.

But the squirrels also discovered the basket. Very quickly, one dominant squirrel claimed it and drove off all the others whenever they approached. We could afford to feed blue jays and one squirrel, so we declared victory and continued this through out the reminder of the summer and fall. It even seemed to work through the winter.

However, spring was a new season and we had to start the whole process over again. I inadvertently did something slightly different and things didn't work the way they had the previous year. So this year we have had a new set of adventures. But those adventures will have to wait for another time.