Cooper’s Hawk Redux

Back in mid-March 2002, our hopes were high.  Our son Dave reported the loud “cak-cak-cak” dawn calling of a pair of Cooper’s hawks in the woods above the guesthouse.  Day after day despite cold, misty rain, and even a snowstorm, the couple continued vocalizing.  Near the end of the month they started refurbishing an old squirrel’s nest a couple hundred feet up Laurel Ridge in the crotch of a large red oak tree.Our guesthouse–circa 1865–is Dave’s home, and its porch overlooks the stream and our access road.  It also provided a good place to erect our spotting scope and watch the courtship and nest-building of what appeared to be a Cooper’s hawk pair setting up housekeeping for the year.

At the end of the month, I spent two early mornings on Dave’s porch, my eyes glued to the scope and the action at the nest.  The first morning I only had brief glimpses of birds flying into and out of the nest.  The next day they worked from shortly after dawn until 9:35 a.m. bringing in sticks for their nest.  Researchers say that the male spends more time nest-building than the female.  The female Cooper’s hawk is also one-third larger than the male, but both moved so fast that even through the scope it was difficult to tell them apart because   they look alike with slate-gray backs and rusty-barred breasts.  All I saw was a flared, banded tail as a bird dove downward and away whenever it left the nest.

During the early days of April we occasionally heard the birds and saw what we thought was the male flying away from the vicinity of the nest, since the female is the prime incubator and it is the male’s job to supply her with most of her food during the 34-to-36-day incubation period.  And then nothing–no more dawn flights, no more movement to or from the nest. Researchers in Wisconsin and Michigan discovered that Cooper’s hawks often build alternate nests before incubation, nests that are approximately 60 feet from each other.  Perhaps this pair had another nest hidden nearby which they decided to use.  The last I saw or heard any Cooper’s hawks that spring was near the fork in our access road when one called and flapped overhead one morning.

Nearly a year later, on April 3, 2003, I crossed the wooden bridge at the same fork.  Suddenly, a Cooper’s hawk flew overhead.  Another swooped in close “cak-cak-caking” and landed on a nearby branch. Could it be?  Was Nature giving me a second chance?  I rushed home to ask Dave if he had heard Cooper’s hawks during March when my husband Bruce and I had been away and he confirmed that he had.

Finally, on April 21 I spotted the nest 40 feet up in the crotch of a large chestnut oak tree 30 feet from the road.  They had built it from scratch of sticks and had festooned it with bits of white pine branches.  It was in riparian habitat, about 100 feet from our small stream, in a mixed deciduous forest with several nearby large white pines.

The following day both Cooper’s hawks were in the nest and after that, whenever I walked down the road, the female was on the nest.  I marveled at her persistence through one of the wettest springs on record especially when I saw that she was an immature.  Immature females do breed sometimes–as many as six to 22 percent of breeding female Cooper’s hawks are yearlings.  Breeding immature males are much rarer and our male was mature.  Although Cooper’s hawks now and then reuse the same nest, they are more likely to return to the same area each year and build a new nest, so I wondered if the male was the 2002 male.  Cooper’s hawks are monogamous during one breeding season, but only some re-mate the following year.  Others take new mates.We never saw them copulate, but they do so after he delivers food to his mate.  Mating is done on the female’s tree perch where she goes to accept his food offering.  One or both of them call which may have been the vocalizing Dave had heard in early March mornings since most mating occurs then.  A month passes before she lays any eggs and in that period an average Cooper’s hawk pair mate about 372 times, close to a world record for any bird species!

Often almost daily rain kept me from watching the nest, but in the middle of May Bruce took an early morning walk and saw a Cooper’s hawk land and lean over the nest.  That was when he found a good spot at least 300 feet from the nest in the overgrown front yard of our former neighbor where I could watch the nest through a gap in the foliage.

On a glorious May 19, tucked among a tangle of wisteria vines, I sat down at 8:30 a.m. and peered through my binoculars.  Almost immediately an adult lightly touched the nest and flew off.  Ten minutes later, first the male and then the female landed on the nest, looked down, and flew away.  At 8:50 the female briefly checked the nest again and was off but at nine she returned, looked around, and lowered herself slowly and carefully down on the nest.

The following day I arrived again at 8:30 a.m. in time to see the female knock the guarding male aside as she flew into the nest.  Such aggression was not surprising. Female Cooper’s hawks nearly always displace males from prey, perches, and nests.  Before settling down she peered into the nest several times.

I was not satisfied with my view from the yard so I moved my operation to the woods about 200 feet from the nest tree and on the same level as the nest.

At first the male protested my presence with loud “cak-cak-cak” alarm calls.  It turned out that his watch perch was almost directly overhead even though I rarely glimpsed him through the curtain of greenery.  But he soon adjusted to me and on May 25 I began an almost daily vigil.

Sitting on my hot seat, elbows propped on knees, binoculars steadied in my hands, I could see the head of the female sitting on the nest, her long tail sticking out over its rim.  Watching her, I moved into another realm–that of bird time–patient, quiet, still.  Blue jays and chipmunks called.  Both are popular prey for Cooper’s hawks, but evidently they are safe when in the vicinity of the nest.

Day after day she sat and so did I.  The faithful male above me quietly “kik-kikked” when I arrived and when I left, letting his mate know my whereabouts.  When June arrived, I began to wonder if the eggs were infertile.  Incubation time is 34 to 36 days, and she had been on that nest for more than a month.  Still, I held out hope that either the eggs had hatched or I had misjudged her actions earlier and she had not actually begun incubating in late April.Then, on June 8, I checked the nest in late afternoon.  She was sitting on it when I arrived, but five minutes later she flew off.  That was when I saw a fluffy white nestling moving around.  It climbed up to the edge of the nest and turning its rear end around, squirted excrement over the side.  I felt almost like a proud parent as I watched its head and body wobbling on unsteady legs.

After fifteen minutes the female landed on the nest rim, looked around and down into the nest, and then flew off again while her youngster continued moving around.  At 4:52 she returned, tucked the nestling under her breast, and sat down.  But she kept looking around, clearly wondering where her next meal was coming from.  Off she flew at 5:00 p.m. and ten minutes later was back.  Two minutes after that the male landed near me and emitted quiet “kiks” while she remained on the nest.  Then she flew off to the transfer tree to receive food.  I heard soft noises but still couldn’t see them.  Shortly after that she landed on the nest and leaned over to feed her offspring.

I suspected that the nestling was several days old and had hatched while we were gone at the beginning of June.  I knew that immature females usually lay less than the average three to five eggs of mature females so I was not surprised that she had only one young.  As the days passed the movement in the nest increased.

On June 15 Bruce set up the scope for me and I finally saw two nestlings.  I also saw the gray carcass of a squirrel on the rim of the nest, clearly prey that the female had brought for her offspring to eat.

The two siblings jousted and one jumped on top of the other.  Then they sat down and bit on one of the nest sticks.  Both groomed their breast and wing feathers.  Already a few dark feathers had sprouted at the upper edge of their wings.

After that I rarely saw either parent at the nest.  They were too busy hunting food for their rapidly growing youngsters.  On June 20 their wing feathers were black along the lower edges and they had grown enormously.

I spent the sunny, breezy afternoon of the 22nd watching again through the scope.  The nestlings couldn’t sit still like youngsters everywhere.  They constantly scratched, stood up, sat back down, and snapped at flies.  Little black feathers stuck up from their backs and wings and they pecked at them and at their small tails which they also tried to preen.

Of the many nests I have watched over the years, this was the first during which I saw more of the young than I did of the parents.  I formed a real attachment to them as they yawned and wriggled, stretched their wings and stood up awkwardly, almost as if they were top heavy.

I never saw the nestlings fight and when they slept they snuggled close.  The next evening I watched as they preened their bellies and beneath their wings and then tried to sleep.  They reminded me of children who have been put to bed but can’t keep their heads down.

Then one stood up, flapped its wings, jumped up and down and stretched.  A minute later its sibling joined it and both poked at something down in the nest–probably prey remains.  They were tottery on their huge, yellow feet and one stumbled and fell as it continued to flap its wings and walk around the nest edge.  The other stayed behind it. I called the leader Bold One and the follower Shy One.

Six days passed before I had another chance to watch the nest.  I arrived at 8:50 a.m., and there was no sign of them except for a slight movement.  Where were the fluffy, yellowish-white chicks?  At 9:05 I saw more movement and realized that they were almost the same color as the tree trunk–their backs a rich, chocolate-brown speckled with large, white spots like polka dots on a dress and their light breasts heavily streaked with reddish-brown.  They looked as big as adults.  Both groomed themselves, especially their breast feathers and under their wings.  Next they groomed their bellies and long, banded tails.  But their faces looked absurdly young in contrast to their fully-feathered bodies.  They were the same size and because they were so large I suspected they were females.

The next day the Bold One climbed down from a branch that formed the crotch holding the nest, jumped up and down, flapped its wings, and then clung to the tree trunk briefly, its wings flailing.  The Shy One approached its sibling and looked over the side of the nest, but it did not follow it up the branch.

They continued such exertions for several days and on the fifth of July both climbed up and down nearby branches and jumped and flapped their wings.  Finally, the Bold One started down a branch and flew about six feet to the nest. The Shy One followed.  The following morning at 9:30, Bruce took a friend to see the nestlings.  Both were perched on the naked branch beside the nest.  An hour later when I checked on the nest they were gone.  I never saw nor heard them or their parents again.  Unlike most fledgling Cooper’s hawks, they did not stay in the vicinity of the nest to be fed several more weeks by their parents.

Still, I was grateful that I had had a second chance to watch a Cooper’s hawk nest.  It was the bright point in a summer that saw the final decline and death of my 89-year-old father.   He and I had shared a love of the outdoors and the creatures of the natural world.  How he had enjoyed my tales of the Cooper’s hawk nest during his last days.