Paul Roberts phawk254@comcast.net via yahoogroups.com
Apr 8 (2 days ago)
to Alewife, Arlingtonbirds

Why are Buzz and Ruby not nesting on 185 Alewife Brook Parkway for a third consecutive year? I outlined some of the possibilities in my email of March 6 I think the most important factor, by far, was about 20 ounces of jet fuel in the form of an immature male Peregrine Falcon.

The falcon has been spending much of the winter on the Rindge Towers. This established a clear competition, because early on the Peregrine competed with Buzz and Ruby for pigeons roosting along Cambridgepark Drive. As winter evolved, Buzz, Ruby and the Peregrine focused on the “cattle” foraging in the “valley” of Fresh Pond Mall; about four “tribes” of Rock Pigeons that roost primarily on Concord Lane and New Street and spend most of the day foraging in Fresh Pond Mall (both sides).

These pigeons traditionally start the day by emerging from their nighttime perches as a flock and flying in low, below the horizon, at the outermost reaches of dawn, so they remain almost invisible as they seek their favorite morning perch, the standalone CVS sign on the west side of the highway. I don't know why it is so important. It just is. It is the highest standalone object in the mall. The lights might provide some heat, or it allows them to see potential predators in all directions. It's the Mt. Olympus for local wintering pigeons, and on a typical morning several tribes will seek to land on it. The first tribe is near the center. Subsequent arrivals find more and more competition for space, like a crowded subway car. As new arrivals land, some are shoved off into space. The refugees seek perches on the T-Mobile Roof.

The ritual is like a dessert cart for Buzz, Ruby and the Peregrine, only it is not dessert. It's the main meal of the day. The immature Peregrine was almost always the first bird moving each morning. His forbidding silhouette would be seen looming over a corner of one of the Rindge Towers. Typically, Buzz was the second bird seen after the first sliver of dawn, emerging from his nighttime roost to perch in a tall tree affording excellent views of his domain, including the CVS sign and Rindge Towers. Ruby would join him shortly thereafter from her separate nighttime roost.

There would be a rustle of shadows, as wisps of pigeons emerged from their roost and flew under the radar to swoop up onto the CVS sign. Perhaps the young Peregrine gave himself a four count before he took off, but he dropped from the sky like a lead weight, disappeared into the distant horizon, and streaked through the air at the pigeons exchanging morning greetings on the CVS sign. The pigeons usually had an all-hands alarm a few seconds before winged lightning struck. The Peregrine would strike from above, exploding into the flock of pigeons as they lofted into the air above the sign. The Peregrine would miss and then, with incredible speed and agility, execute an unbelievably sharp turn and try to separate one pigeon from the rest of the flock. Sometimes he did so, sometimes not. However, I never saw him capture a pigeon off the CVS sign. He might make 5 or 6 passes at the flock in the air, throwing the entire pigeon community into consternation. They would wheel in the air time and again, trying to find a safe place to alight, but never very sure about it. These pigeons got more good aerobic exercise before sunrise than an entire running club. It would often take 5-10 minutes for them to finally alight somewhere. One day it took them 25 minutes before they felt safe touching terra firma.

Buzz and Ruby hunted the same herds of pigeons, but they hunted in a very different manner. Buzz and Ruby would be perched for minutes, sitting still and likely invisible to pigeons, who best perceive movement. (With the Peregrine, they see the movement, but the bird is moving so fast the pigeons' reaction time is life-threateningly short.) Typically, Buzz would drop out of the tree and fly below the radar, coming in low, with a minimum of flapping in the dark hollows of dawn, beneath the level of the CVS sign. The pigeons always had someone sound the alarm call before Buzz arrived. Somebody would see that torpedo in the dark waters of Fresh Pond Mall. I could generally count at least a 4-7 second lead time. Typically, pigeons would jump off the platform first and then raise their wings to lift and separate. Sometimes, birds in the center had to work their way in the rush to the edge and jump off a little later. Buzz had a chance for them. Usually, however, he missed. When he did miss, the pigeons had several options. Fly to Fresh Pond (east) and reconvene on several lampposts, or reunite as a flock in the air, wheel around, and return to the CVS sign… because Buzz made only one pass at the sign. Early on, the question was raised as to whose “cattle” were these pigeons? Whose brand did they wear?

There is something magical about that CVS sign because the pigeons really do prefer to perch there first thing on a winter's morning. When the Peregrine attacked, he chased after the flock trying to separate one bird out and driving the flock to all corners of the mall in pursuit. When Buzz attacked, it was one and done, unless he missed and continued to get pigeons resettling on lamppost in Fresh Pond Mall. Thus, pigeons could comfortably wheel once and return to land on the CVS sign, which they often did.

Many times, Buzz would miss, but he would use the sign as an aircraft carrier, landing there and remaining perched on the sign, often to approach the 185 nest. The pigeon flock would wheel once, return, and would be about to alight on the CVS sign when someone noticed the damned hawk was still sitting there. Abort! Abort! They would wheel around once again and come into the sign once again to alight, when someone noticed the damned hawk was still there. Abort! Abort! One morning, one tribe wheeled around the mall 37 times, attempting to land on the CVS sign each time, only to discover that Cambridge's most famous Red-tailed Hawk was still sitting there.

This was the typical situation. However, not all days were typical. They became frequently less so, as soon it became clear that three hawks were trying to raid one herd of cattle. Buzz and Ruby upped the ante. Buzz started attacking earlier, before the Peregrine. Before the end of the winter, Buzz was launching when the first pigeons were landing on the CVS sign, before they ever had a chance to get settled. In fact, the pigeons seemed to modify their behavior as well, with one pigeon landing on the sign well before the entire tribe landed. I wonder how that individual was selected . . . .

The Peregrine might be young, but he is not stupid. He recognized what Buzz and Ruby were doing and started going after Buzz, especially when Buzz would venture into Fresh Pond Mall after an attack.

Buzz and Ruby adjusted. First, Buzz would launch at the sign, followed a two count later by Ruby. This yielded two benefits. One, Ruby would have a second strike capability with the pigeons, catching the refugees by surprise. Second, if the Peregrine stooped on her mate, Ruby was there to help defend Buzz. She is larger and more powerful than her older mate and could complicate things for the “kid” who was causing such turmoil in the neighborhood. Or maybe she was just hungry as the time to make and lay eggs approached and she just didn't want to wait for Buzz to feed her.

On one or two occasion I saw something pretty impressive. I don't know how thought out it was, but it was impressive nonetheless. Buzz launched a long attack across 16, into Fresh Pond Mall pursuing a flock of pigeons on a lamppost. In case he missed, Ruby launched farther north and cut across the wheeling flock of pigeons, coming from an angle that the pigeons would not be expecting. I have frequently seen Aplomado Falcon pairs hunt this way, working large flocks of Red-winged Blackbirds or grackles with the two-step attack. I've even seen juvenile Peregrines at Plum Island do it with shorebirds at Sandy Point. I never saw it work for Buzz and Ruby, but it seemed very smart.

When the Peregrine found Buzz poaching in his territory, especially on the Fresh Pond Mall, he would strafe Buzz. He would come zooming in and shoot down at Buzz. I never saw him drop his talons, which would be akin to the “nuclear option,” but he would be like a teenage driver playing a game of chicken, coming as close as possible without striking. Buzz could feel the wind from the Peregrines wings. Usually, Buzz would rather calmly turnaround and proceed back to the shelter of Fresh Pond, or the west side of the parkway. Once or twice the falcon went at Ruby. She is larger, but younger and less experienced than Buzz, and several times she rocked in the air to avoid the world's fastest, and maybe most audacious bird.

These skirmishes were increasingly frequent during the winter. We began to question if this could not augur well for Buzz and Ruby nesting on 185 again. Immature Peregrines had wintered on Rindge Towers at least several times previously, and I can't recall any reported conflict with Buzz breeding in the area before, but that doesn't mean it didn't happen. Maybe this young Peregrine, like all the others, would leave as winter was drawing to a close.

The events of February 10, described in separate posts by John Sharp and by me, were heart wrenching, and not only for the human observers. I will never forget the look on Ruby's face when the young Peregrine stooped on her, screaming, trying to knock her off the roof of 185. I think this day must have been the turning point, at which point Buzz and Ruby came to the conclusion that they could not raise a new generation on 185 under these conditions. Ironically, I was leaving on a two-week vacation in Texas the next day. Fortunately, my daughter Laura had volunteered to pick up daily observation of Buzz and Ruby for me while I was gone.

I was worried, very worried, about what was going to happen while we were gone. However, very little happened. There was a little harassment from the juvenile Peregrine on a day or two, but nothing like the 10th. Buzz and Ruby continued to pay attention to the 185 nest without much aggravation, but they also worked more on their pine tree nest.

The final tipping point was likely February 29. At 6:03 a.m. Buzz and Ruby were perched together, both having arrived from their separate nighttime roosts. Ruby then took off and flew directly to the pine tree nest. A few wing beats later, Buzz took off and flew directly low and straight to the roof of Fresh Pond Mall, just south of Petsmart. I had not seen him do that maneuver all winter. Buzz was bearding the lion in his den. The Peregrine dropped from the Rindge horizon, disappearing into the shadows spawned by dawn. Suddenly, he was strafing Buzz, swooping up, reversing direction, and tracing that swoop back to strike at Buzz again. Not hitting him, but trying to drive him from the perch. Buzz jumped up at the Peregrine to defend himself. Twice. The Peregrine began rocking back and forth, diving at Buzz. 8 times, 9 times. 10.11. 12. Buzz kept jumping up as the Peregrine swayed back at forth at him. He must be exhausted. 13-14-15-16-17. Incredible.

The Peregrine had been rocking in a deep U, diving on Buzz from the north and south end of this deep U, like a Hummingbird courtship flight. Going about 15-25 feet high, swooping down at Buzz and then up, turning around very tightly and swooping down again. It keeps going right at Buzz, passing just over his head, without dropping his talons. Buzz is jumping up at the falcon, but is not raising his talons, is not rolling over on his back to defend himself. Buzz is below the Peregrine. 18. Goes up after the Peregrine, and forces the Peregrine to lift up, 19 sorties at the Peregrine. Buzz finally takes off, heading towards the CVS sign. The peregrine strafes him on the way to the CVS sign. There is one pigeon on the sign, but Buzz ignores it and lands there, where the Peregrine rocks 2-3 times more at him. Buzz had been fairly blasé in his return flight to the CVS sign, as though the falcon was only a very minor irritant. However, after several passes by the Peregrine while he was on the CVS sign, Buzz executed a strategic retreat into the woods of Fresh Pond Reservation.

I think the whole event was incredibly courageous of Buzz, but it clearly revealed that he would not be allowed to hunt food unhindered in Fresh Pond Mall. That in 2012 none of his young hawks would be able to fledge into the Whole Foods parking lot on their first flight without being harassed by the Peregrine even before being hassled by mobile steel hawk crushers, (aka as cars) and harassed Whole Food shoppers with cell cameras in hand.

If there was any lingering doubt, it was shed on Friday March 2. At 6:59 a.m. Buzz dropped to the ground in front of 185 as if to catch a vole or mouse, maybe twenty yards north of a friend and me. I thought Buzz had caught it, ands clearly he had too, but he jumped up empty handed and pounced again. Suddenly, the Peregrine was strafing Buzz on the ground, while hunting rodents, not pigeons. The Peregrine made only two passes. Buzz jumped up both times the Peregrine rocked over him. Buzz then took off, pursued by the Peregrine, disappearing to the north of 185. We raced around the building, where we found Buzz had actually flown back to where Ruby was perched in a honey locust tree, and with the adrenalin still pumping through both hawks, they mated, while the Peregrine returned to his lonely watch over the Fresh Pond valley beneath him.

That afternoon, I looked at the photos I had taken that morning and learned something more. I had been photographing Buzz hunting on the ground in front of us. Unknown to me, I had captured the two passes by the Peregrine, which took only 5 seconds. More important, the photos revealed that Buzz had leapt several feet into the air and reared on his back in the air, swinging his talons up over his head in self-defense. The photos were remarkable because two of us had been watching this and neither of us had actually seen Buzz roll over on his back in the air and swipe his talons over his head before returning to the grounds. We had seen him straight up jump up and land. The camera revealed that each leap, swinging his legs up and over his body, took no more than .2 seconds, that is two tenths of a second, before his talons returned to the ground. It then dawned on me that this must have been what he had been doing on February 29th 19 times. At that time I was viewing it perhaps a hundred yards away.

After the harassment on the ground on March 2, Buzz was not intimidated. About a half hour later, Buzz disappeared to the east over TJ Maxx. He drifted back over the store and did a low, obvious, territorial stutter flight over Rte 16, landing on the apex of the atrium at 185. He sat there, king of all he surveyed, for more than 5 minutes, apparently unafraid of the Peregrine. He did a slow, lazy flight over 185 and disappeared to the west, but suddenly he comes streaking over 185 shooting east over Fresh Pond Mall, disappearing to the east. I thought he must be going after pigeons, but when I went around the north end of the mall, there was Buzz sitting in a large deciduous tree just south of the movie theater, and just a little to the south and below an enormous adult female Redtail. He sat there as though they didn't recognize each other. Buzz flew back towards 185, doing another low, slow stutter flight, before landing on the pinnacle of the atrium at 185 again. Suddenly, at 7:56, he exploded off the atrium. The female Redtail that had been in the tree had flown towards Buzz and was crossing Route 16. Buzz went right at her. I think he may have bumped her. Whatever, she rocked in the air as she quickly turned and flew east like a bat out of hell, towards Danehy, with Buzz hot on her tail. Buzz was gone for over 20 minutes.

Note, there was no mention of Ruby on March 2, because she was not to be seen. For the first day in months, she was nowhere near Buzz. She was not helping defend the territory because she was on the nest… The pine tree nest. Nott 185. She was either heavy with egg in process or actually incubating the first egg she had laid. The evidence is circumstantial, but convincing, complemented by the fact that all morning March 2 Buzz had been making low, slow, territorial stutter flights around 185 and the new nest. Buzz and Ruby had achieved a new stage in their life together; their third breeding season together, in a new nest in a new location, but on familiar territory.

Since March 2, the world has changed. Pigeons no longer alight on the CVS sign shortly after dawn. They are sex-crazed, courting and breeding by the hundreds. The hunting routines of all the hawks have changed. I've seen the immature Peregrine far less frequently, and not seen anything like the interspecific confrontations of the winter. Ruby is on the nest, and the focus is on the world's next generation of Redtails.