John Blakeman on Pale Male Learning From Experience

Pale Male Comes Out and Lola Goes In

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Red-tail expert, John Blakeman weighs in on my theoretical comments concerning The Mystery Of Red-tail Survival in Territories with Rat Bait and Poisoned Rats

Donna,

Your thoughts on rats poisoned with anticoagulant rodenticides and Pale Male’s potential predation of these are extremely incisive. Your training and experience in field biology was evident.

Let me add my comments.

The first point. Red-tails (and almost all other predators) are instinctively attracted to prey animals that do act weird, ones that are staggering, slow to react, or otherwise revealing themselves to be an easy kill.

That, in fact, is the major ecological “function” of predators (to be teleological, which nature isn't). As I've posted earlier and elsewhere, red-tails both in Central Park and out in the wild don't ever control prey population numbers. The continuing numbers of rats, pigeons, and squirrels in Central park attest to that. But they do tend to remove from those populations individuals that are sick, injured, or dumb, thereby contributing to the populations’ overall “health” (properly, their ecological “fitness,” which shouldn't be confused with our personal health and the excess of food we've eaten all winter.)

So, as you've mentioned, a newly-fledged eyass attempting to take its first prey in June or July would eagerly pursue a staggering, poisoned rat out in the open. It couldn't resist.

But, as you've also described (very eloquently without objectionable anthropomorphisms), Pale Male could be deliberately avoiding poison-stunned Norway rats in the ways you've described.

Although one of the great advantages of the bromadialone poison is that rats can't taste the stuff, it is possible that Pale Male was able to detect some untoward or objectionable taste or odor in a poisoned rat he captured and then spit it out. He’s got plenty of other food in Central Park, so he had no hunger-driven impulse to consume the specimen. (He eats like so many in NYC can, with great food variety and in ample quantities, ubiquitously available.) So he could afford to discard a rotting (not yet rotten) rat.

Or, he could have learned not to take staggering rats in the following manner. Falconers (more than anyone else) know intimately how hawks’ almost mysteriously connect and memorize every behavior used to take game. Pale Male knows this when he takes his CP prey. He has learned through memorized experience exactly how the target prey animals behave in every circumstance. Hawks tend to memorize and recall every hunting flight they conduct, learning from each one.

When he might have taken a poison-stunned rat, its behavior was impressed in his brain even before he took the first bite. When he tasted the blood of the rat and detected circulating liver chemicals resulting from the poison, he may have made the connection. Yellow flags went up in his memory. There’s something wrong with staggering rats. Don't bother to capture one.

The lesson may have (probably did) require more than a single poisoned rat. As the product safety information for bromadiolone indicates, a predator is unlikely to consume enough of the chemical from a single rat to kill the predator. But Pale Male may have become sick from a single rat. His brain is perfectly programmed to connect the dots between the sick rat and his discomfort.

You are absolutely correct. Pale Male could indeed have learned not to kill or eat poisoned rats. Even more accurately, you've noted that this wasn't through any human-like intellectualism. Rather, it was through natural selection.

Nonetheless, our beloved red-tails are, in their own curious and interesting ways, true avian intellectuals (the experienced adults, at least).

–John Blakeman

The issues with unenlightened people and with poison here in Wisconsin are sometimes dire. Here are a few words from a wonderful local rehabber, who everyone calls the Bird Lady, and as she wishes to be anonymous....

(The following is not for the sensitive. Some may well want to skip it.)

Hi Donna,

I don't have a lot of experience or data with rodent poisonings, although they occur very often. Farmers use a type of chemical to kill starlings and pigeons, and the predator birds eat the sick birds and are poisoned. I had a bald eagle last year that was so sick, he almost died.

It is hard to find out what the exact culprit is unless you know what you are specifically testing for. And often by the time the bird is found, whatever it was has passed and all you have are symptoms. This past year guys were mixing rodent poison or fly bait with cola and leaving it for the coyotes and raccoons eat. Nasty death, and then the predator birds feed on them and become sick as well, resulting in death.

Comparatively, in some ways, we could count our blessings.

Donegal Browne

Lola Sticks Tight and John Blakeman on Bromadialone

Lola stands. Airing the eggs?

She preens.

She checks the eggs.

And she's down again...Sticking tight.

The Response to Katherine Herzog's questions from the remarkable and I must say speedy answering John Blakeman:

Donna,

I've never encountered a raptor poisoned by bromadialone. I know only what I can read about this anticoagulant rodenticide in a common Google search.

It seems clear that raptors that consistently consume rats or mice being killed with the chemical can accumulate it and suffer secondary effects and death. I'm not impressed with the field safety of the material in regard to raptors that would capture and consume rats ailing from the poison. A single consumed rat wouldn't likely cause any lingering problem. But a hawk consistently taking poisoned rats would likely suffer.

I think there is one mitigating factor, at least for diurnal (day-active) red-tails. A rat slowly bleeding to death from bromadialone is not so likely to be out walking around in daylight where a hawk could capture it. Most afflicted rats are likely to curl up in some typical wall, attic, sewer pipe, or other typical rat haunt while suffering.

If a dead rat were to be fully exposed, a red-tail will often drop down and take the animal. But I doubt that many dead or dying rats are out in the open where an NYC red-tail could take them.

Our red-tails spend most of their hunting time looking for inattentive pigeons and fully exposed and vulnerable squirrels and rats.

Lastly, if the Central Park red-tails were poisoned in any way, their behaviors would change discernibly. They would become sullen and inactive, revealing reduced energy and activity.

And I don't think Lola's increased sitting time reflects any of this. There is an outside chance---very outside this early in the game---that she has begun to detect minute muscular vibrations of developing eyasses. Perhaps there are some viable embryos this year and she's contributing increased maternal efforts toward their maturity.

Let's hope, anyway.

--John Blakeman

Everybody has their fingers crossed on this end let me tell you.

Crossed fingers are for luck, right? Which brings to mind one of the many conversations that occur around The Bench, as to just why Pale Male hasn't succumbed to a poisoned rat in all these years. (Knock wood.)

One speaker's opinion was that he was just incredibly lucky. Luck certainly is helpful and I'm not saying that Pale Male doesn't have luck, but might there well be something more to it than that?

Is is just lucky that he doesn't have much of a taste for rats? Which he doesn't of course. One rarely sees Pale Male eating a rat. Nor does he bring them to Lola on the nest that often after the gift giving phase of breeding is over. Evidently Lola does have a taste for mammals as rats and squirrels are the bulk of Pale Male's pre-copulation gifts most years. And come to think of it why hasn't Lola, the red meat eater, succumbed? (Knock wood.)

Having watched Pale Male for some years now, it's extremely apparent to me that he is one very smart, very experienced, and very urban-savvy Red-tail. And Red-tails being generalists, learn from experience. It's not just all wired in and that's that.

A couple of seasons ago, I arrived at the Bench and asked about the hawks earlier doings of the day. Lola had been perched on a branch with a rat. Pale Male arrived and started to beg for a bite like an eyass would. Evidently proper manners when wanting to eat off of someone else's plate in Hawk World.

Now this does occur sometimes in early Spring, possibly as part of the budding courtship. And I know of one case where Pale Male begged for a bite of squirrel and Lola just picked it up and flew away with it. But in this case I was told he was extremely insistent and got rather puffed up and even slightly threatening. Not his usual at all. Besides being a polite hawk, Lola is bigger than he is, and it was her rat. Evidently she got the message and backed off a bit. Pale Male came over, looked at the rat, took the tiniest of bites, paused head down and then flew away. The anecdote teller laughed and jokingly said,"He looked like her taster."

This got me to thinking. Does Pale Male somehow know if it's a "bad" rat?

John Blakeman is right of course that few rats, poisoned or not, appear in the daytime. And a poisoned rat is likely to be out of sight somewhere, but it does take several doses usually to kill a rat and if you do see a rat in the open in full daylight it's 99% positive it's a poisoned rat. Especially with the anticoagulant poisons, the rats, usually the young ones, come out into the open to look for water...but they don't act like a normal rat. Is it possible that for whatever reason Pale Male knows not to eat them?

First of all they're out in the full daylight. Second they aren't sticking to cover. And third they tend to "act funny". They bumble around, stagger, and just look weird. Now, if I can tell that they're "acting funny", you know Pale Male, master of many edible specie's behavior, can tell too.

As a young hawk did he get a touch of poison from a "funny acting" rat? Did the rat also taste a little "funny"? Smell a little "funny"? So he didn't eat much, but even so he felt really bad for awhile. Lost his appetite for rat in general but also His Nibs now wouldn't eat a weird rat even if he were starving. Therefore why would he give his mate or his young weird rat? He wouldn't even want it in his beak. Yuck.

Now, thinking that he was actually tasting Lola's rat for poison may be a bit far fetched but it did get me thinking. And hey, one should never sell Pale Male short as we've learned over and over again. Come on, just who figured out how to hunt pigeons for instance?

Okay, you say, he's not a person for goodness sake, he's not intellectualizing this whole thing. He's a hawk! They don't make those kinds of connections. Maybe, maybe not. But as a very small child, I once was hit with a stomach churning virus after eating a bowl of chili. Now it turned out that it was a virus not food poisoning, other people got it at the same time who hadn't eaten the chili. But for me as a three year old, an age not big on intellectualizing or correctly putting two and two together, which I didn't, I never wanted to see another bowl of chili. I didn't want to smell chili. Anything to do with chili gave me a lurching physical response. Chili equaled upchucking. It had nothing to do with rational thought, my reptilian brain KNEW not to do it again. I didn't intellectualize and decide not to eat a bowl of chili at the same time I was having a stomach virus. My body learned from experience.

You're not going to say that Pale Male doesn't learn from experience are you?

I thought not.

At any rate, when I start to feel too fearful about the Park's resident Red-tails getting poisoned, I think that maybe, just maybe, Pale Male's example of not eating "funny acting" rodents may have passed on to the others just as his pigeon hunting techniques have.

Of course, I still fear greatly for the fledglings as they innately go for the easy catch and most likely have yet to watch an adult not eat something funny acting.

That's where your luck comes in. Luck, or in my more fanciful moments, where a watchful experienced Red-tail, who will menace you away from the "bad" ones, comes in.

Donegal Browne

P.S. That doesn't mean that a courteous letter to the Central Park Conservancy expressing your sincere concern about rat bait in the Park's Red-tail territories particularly during breeding and fledging season isn't in order. Friendly reminders are always in order when people may have had something slip their minds.

And don't forget a note to The Cathedral Church of St. John the Divine about their rat bait as well. They honestly have probably never even thought about it at all. Why would they? They aren't all Hawk Watchers...yet.

TOMORROW: RATS! WHERE, WHY, AND HOW TO CONTROL THEM WITHOUT POISON

Pale Male Tempts Lola and Estimated Hatch Date for the Divines

Pale Male stands with prey at his feet giving Lola a chance to get up and have some dinner.

Concerned Hawk Watcher and pollen engulfed reporter Katherine Herzog weighs in with a report from The Bench, concerns about Central Park rat bait stations, and a question for John Blakeman, our Ohio Red-tail expert.

Hey, Donna-

Been a bit under the weather with the great fluctuations in temperature...trying to get over a cold and my raging pollen allergies! Hope all is well with you.

Following is a short report from the bench.

Central Park - 5th Avenue "Hawk Bench" Tuesday, March 27, 2007 (Sunny, 78F)

2:30pm to 5:05pm:Comment at the Hawk Bench from long-time birder, Joanne, "ok, I've had it with this heat....can't wait til winter". Yes, Virginia, there is global warming and I'm not looking forward to 35-degree-higher-than-normal temps in June/Jul/Aug....119F? But let me not begin my climate change ranting!

We've noticed a behavior pattern change with Pale and Lola that is very different from when she started laying eggs on March 10th....she is really quite content to sit and sit and sit....with very short breaks from her incubating chores and when Pale arrived at the nest at 4:37pm with a juicy half-pigeon, Lola ignores it completely! I guess she doesn't require that many calories sitting stock-still in the nest for hours.

After waiting for 20 minutes for Lola to take interest in the food...Pale finally took off with it into the Park. She calmly adjusted her position, preened and looked none the worse for lack of victuals. (Earlier in the month when she started laying eggs she was famished and ripped into the food immediately...now she is very blase and Pale is not coming around as often to sit near the nest.)

The recent pet deaths from rat poison reminded me, once again, that our beautiful park is festooned with rodent "bait stations" of a rodenticide called: BROMADIALONE. From info on the net from the Cornell Lab of Ornithology and Tufts University, raptor rehab people it's amazing we still have Pale Male and Lola still so healthy after all these years of rat and mouse consumption. Is it that their "healthy choice" meals of Grey Squirrel and Rock Dove (Pigeon) that keeps them from suffering serious health effects? The referenced labs are quite definitive about the weakness and deaths of raptors that come into their facility....suffering from secondary poisoning from this particular chemical formula.

I think it might be a stretch to conclude that the RTH nest failures are due to this problem (both on 5th Avenue and the CPS nest) but I think it's most likely the demise of most of the park's Eastern Screech Owls is connected to this poison. After all, except for an occasional small bird caught at sunset, the majority of the owl's diet is mice and young rats. And some of the "bait stations" are situated close to the 5th Avenue nest and a few meters from the Ramble, Central Park's wildlife nature preserve!

Is it possible to bring, the wonderful Mr. Blakeman in on this subject? Would really appreciate any insight he could give on this topic.

All the best, Katherine

Isolde, Mom of the Divine Pair, on Gabriel's Horn Photo: Donegal Browne

Robert Schmunk's ( http://bloomingdalevillage.blogspot.com/ ) reply to my questions about just what might be the time frame for hatching behind St. Andrew's elbow up at The Cathedral Church of St. John the Divine. Refer back to Isolde and Tristin Caught Switching.

Per my blog posts, they were seen together outside the nest on Thursday the 15th.
Isolde was sitting in the nest on Sunday the 18th, but she was sitting high enough that her head could be seen at least once. But she then disappeared without my actually seeing her leave, which may or may not mean a lot.

Monday the 19th was the day that she was sitting in the nest 5 minutes after sundown.

Tuesday the 20th she was standing in the nest in an odd posture, which has made me wonder if she was laying an egg. Based on all that, I think they're running a schedule a week or so behind PM and Lola, and about the same as the Fordham hawks.

So I'm figuring hatching around April 26th.

Lovely of the hawks to possibly have staggered the hatches for us, isn't it?

Donegal Browne

Isolde amd Tristan: Caught Switching. It looks like Eggs!

ISOLDE ARRIVES ON THE NEST

Robert Schmunk of http://bloomingdalevilliage.blogspot.com and I had been discussing whether or not the Cathedral nest was deep enough and dim enough so that there might well be times in which there was actually a hawk on the nest but one just couldn't see it.

The answer to the question...YES.

Here are Bruce Yolton of http://urbanhawks.blogs.com/ and Rob's sightings that clinched the answer.

Bruce and I were at the Cathedral today at 5:45 p.m. A hawk landed on Gabriel and a moment later flew down to the nest. It perched on St. Andrew's hand for a bit. I then made to move toward another location to see if I could get a better picture, and while I was at it there was apparently a switch-off at the nest, as Bruce says that the hawk that dived out a moment later was not the one we saw on the hand. The hawk that dived out went up to Gabriel after circling over St. Luke's a few times. Looking at pix afterwards, it was clear that the hawk first seen on Gabriel was Isolde, but that the one afterwards was Tristan.I had seen Isolde on Gabriel's horn at 5:00 before she flew off to the Great Hill, so it looks like Tristan was on egg duty from 5:00 to 5:45. One thing the episode also demonstrated is that the nest is too deep to see a hawk which is on the eggs. Before and after the switch, no hawk was visible in the nest.

rbs

Now if we could just figure out when the last time anyone saw both Isolde and Tristan out and about at the same time, we might have a ballpark figure of when they started to brood and therefore a vague idea as to when the eyasses might be hatching. D.B.

What Is Going On Here?

So I'm minding my own business, attempting to get some pictures of the Sandhill Cranes and suddenly there are four kitty feet and a partial kitty tail at the top of the field of view. Wowie zowie, I better widen that out a little.

Does Kitty think he's really going to get anywhere with all those rather large birds?
All the cranes and geese are keeping an eye on Cat who is wearing a lovely green cat tag and collar. One gander in particular is heading towards the sitting goose. Cat has stopped stock still and seems to be staring towards the barn.

Cat now stares at the sitting goose.

(Pitiful isolation of Killdeer.) Follow the line of the field to the very edge, far left of the photo above. No really, it is there, honest. I didn't see him while I was watching the sequence live either.

Suddenly Cat goes into hunting mode, neck and head stretched forward, tail up, and rapidly heads into the field. The Gander next to the sitting goose is in hissing posture. I've been whacked by geese wings, and it's intense. I figure Cat has probably been thumped by geese himself as he lives on a farm so he is no longer interested in heading toward the goose. Unless it's some kind of ruse.

Cat turns quickly and looks left.

The Killdeer on the verge comes up and gets Cat's attention and distracts him from going whereever it was he was going in such a hurry. Hard to see, but the Killdeer is right where the cat is looking, on the edge of the cornfield. Follow the second board on the left of the doorway of the building down to the field. He's there.

All the birds watch Cat as he abruptly switches direction and heads off right fast.

See the Killdeer on the verge between corn field and grass to the left of the cat. It's near the edge of the photo. Why did Cat change direction and why does the Killdeer look like he's chasing him and the cat is allowing itself to be chased. I haven't found it in the photographs but I saw another Killdeer who was in a freeze between two

corn stalks just a foot and a half from Cat's current position.

Then...my battery went dead. Notice the sentinal cranes are watching and the two others have gone back to foraging. Why is Cat just sauntering up the hill how. What happened to the other Geese? The second Killdeer?

In fact what happened here at all? The discovery in the photographs of the Killdeer helps some but still...

Donegal Browne