Last Martin Fledglings Being Caught By Cooper’s Hawks

[Steve Kroenke]

Last Martin Fledglings Being Caught By Cooper’s Hawks

Our last few pairs of martins are finally fledging their young and the Cooper’s hawks are eating some of them. The other day a lone SY female martin fledged her two last babies from one of my gourds; her SY mate had left the family earlier and she was raising the young alone. She chose the slaughter pit to assemble her two youngsters. This is an area located about 300 yards south of my colony with utility lines and a dead oak tree. It is a deceptively perfect place for martins to establish a family assembly site for their fledglings. It is a killing field where hundreds of martin fledglings have had their lives taken away since I have had my colony here. Cooper’s hawks have killed numerous martin fledglings at this site. The martins never learn and there is nothing I can do about it.

At around 11:30 am that morning I heard the blood curdling screams of terror from the skies as numerous martins were attacking the chief martin fledgling killer, a large mature female Cooper’s hawk that was heading directly for the two youngsters which were perched in the top of the dead oak tree. The hawk was several hundred feet up and circled the area several times before plunging straight down and snatching one of the martin fledglings from the tree. A flock of martins went berserk and hopelessly mobbed the killer as she carried her prize to a nearby woodlot to be eaten.

The remaining martin fledgling didn’t even fly! Now did the mother martin take her baby somewhere else? NO! This would be a fatal mistake.

I watched the female martin continue to feed her last baby in the top of the oak and I just knew it was only a matter of time before one of several Cooper’s hawks would come over to catch the youngster.

Later in the afternoon, I was outside when again I heard screams of terror from some martins flying high above our colonies. Coming from the north and way up in the sky was a male Cooper’s hawk which is smaller than the female. This male hunts somewhat like a peregrine falcon and comes high up over our colonies, circles while looking for exposed martin fledglings in trees or on utility lines, and then drops like a rocket to ALWAYS catch his victim. When he appears like this every adult martin in our colonies emits alarm cries and climbs like a bullet to get above and mob him. During the height of the fledging process in mid June, hundreds of screaming martins would scramble like fighter pilots and climb at terrific speeds to attack this high flying male hawk as he prepared to hunt their fledglings.

It didn’t take long for him to see the martin fledgling in the oak tree and he circled over the area at several hundred yards up. Then he folded his wings close to his sides and plunged toward earth like the death asteroid at a near 90 degree dive! Unbelievable screams of terror erupted from the martins as some even followed him down in his power dive. But there is NOTHING they can do to prevent the final outcome.

This time the martin fledgling actually flew from the oak tree and tried to bolt downward to escape the hawk. There was NO escape and the Cooper’s hawk easily snatched the martin fledgling after it had flown no more than 20 feet.

The hawk dropped close to the ground with his prey and flew across an open pasture to reach a woodlot. There he would eat his meal in peace.

Some of these last remaining martin youngsters will no doubt meet the Grim Reaper when they fledge. The hawks know the area well and periodically check out all the places outside our colonies where martins tend to assemble their fledglings. Some of the hawks make occasional high flights over our colonies as they look for martin fledglings. And the hawks are fully aware of the profile of a recent fledgling when perched, its vocalizations, its amateurish flying abilities, and the shorter rounded wings and tail. Once the hawk sees a vulnerable martin fledgling there is usually no chance that the fledgling will escape.

I have kept records of the number of martin fledgling kills I have observed. So far the total is 36 and all have been by both male and female Cooper’s hawks. The kills have been outside my protection area, usually several hundred yards away from our colonies. I suspect that easily three times that many kills have occurred outside my observational range.

Most have involved the hawks plucking martin fledglings off utility lines or from tree tops/branches though some youngsters have actually flown and tried to out fly these speedy and agile Accipiters; none escaped the Grim Reaper. Huge flocks of adult martins have often mobbed the hawks which make no effort to hide their approach. The hawks KNOW that the martin fledglings are easy meat and will often not even fly away. The hawks may be high up and dive down like peregrine falcons at almost a 90 angle or at half that grade. Others approach at lower heights just above the trees and just grab the martin fledglings with little effort or catch them during a short twisting chase. And some hawks may just “move” through the tree tops, find a fledgling, and simply pluck it off a limb.

The Cooper’s hawk is the number one enemy of martin fledglings in our colonies and predates many youngsters each year. With so many vulnerable fledgling martins flying about, it is only natural that bird eating hawks will be attracted to the area and feast on this prey base. I can for the most part keep the hawks out of our yards and from preying on martin fledglings assembled nearby. There is nothing I can do for the most part in stopping these hawks from predating fledglings several hundred yards away. I can only watch.

Steve

[redfinch]

What a bummer, Steve. Sorry you have to watch such a sight and be helpless at that. Such is nature. Cruel at times to say the least.

[Daniel Airola]

Steve -

I know you understand population dynamics, but maybe it is worth noting that your loss of perhaps 100 fledglings, while seeming alarming, represents not more than 10% of the >1000 total number of young fledged from your site (based on one of your other posts). I bet this rate of predation is higher than at smaller colonies, but nonetheless you've produced 900 more young than would otherwise have been produced. And that is quite an accomplishment!

When I observe death of birds in the field, I am reminded of something my first Wildlife Management professor, A. Starker Leopold, said 33 years ago, "If most of the animals produced every year didn't die, we'd all be up to our necks in Mourning Doves". It puts things a bit in perspective.

Congrats on a great year. I wish I had your problems in Sacramento (i.e., so many birds that they attract predators). You are personally hosting more pairs at your site than nest in California's 15 million acre Central Valley.

[tonyg]

Wow, don't know how you can stand to watch their onslaught. I know natures cycle can be cruel but I made up my mind a long time ago that I would do what ever it takes to protect my martins. They have enough of a rough life as it is with the migration, weather,sparrows,starlings,mites, predators plus the trip back. For the 3 to 4 months they are here and what they bring to my wife and I's enjoyment, I make it as comfortable as I can for them....they are family.... Its been a very good year for us.

[Steve Kroenke]

Hey Redfinch, Dan, and Tony,

Predation is an emotional issue for martin landlords because we are often so bonded to "our" birds! These little martins fly thousands of miles to nest in our yards and we try to provide a safe haven for them. Then some are caught by predators and we often respond emotionally to the act. It is almost like we are losing a "family member". However, martins are wild birds and they must face danger from predators just like all other creatures.

Though I am not a scientist, I love science and agree with the concepts of natural selection and survival of the fittest. I understand about predator/prey relationships and try my best to balance my emotional attachment to "my" martins with the actions of their predators. It is not easy! Predation helps keep populations under control, strengthens the prey base by weeding out the weak and sick, and allows the strong to survive and continue breeding. But we martin landlords are still human and emotional and attached to our martin colonies!

I mainly try to give martins a safe place to nest in my yard and try to keep the predators at bay there. I can do nothing to stop predation outside my sphere of protection.

Dan, yes only a small percentage of our martin fledglings are lost to Cooper's hawks each season and a good number of martins are produced at my colony. And fortunately, the hawks tend to ignore the parent martins and focus on the more vulnerable young. So, I try to focus on those factors rather than the act of predation which is dramatic at times. But man, it is still hard to watch the attacks and not get emotional about it. I don't know if I will ever be able to totally look at predation on "my" martins from complete objective/scientific perspective. I appreciate your comment about this.

Thanks for all your comments.

Steve

[Guest]

Steve
I would like to complement you on your powers of observation and ability to make your words paint a picture. Your description reads like a short story. I can easily visualize what you are describing. Thanks

[Steve Kroenke]

Hey Roykite,

I am glad you enjoyed the article. I try to provide a lot of detail with my observations of nature and study wildlife very closely.

Here are some links to other articles of mine dealing with predation that you may enjoy reading:

http://purplemartin.org/forum/viewtopic.php?t=923

http://purplemartin.org/forum/viewtopic.php?t=4515


Steve

[Daniel Airola]

Hi Steve -

I certainly don't want you to give up any passion for your martins - not that I think you could! It's the passion for martins that keeps us, and them, going. Thanks for all your great work.