It’s hard to tell from the camera views but it looks like Mariah laid her fourth egg in the early hours of April 5, probably around 1:40AM. That’s about 57½ hours since the last egg. Will there be a fifth? Keep watching to find out!

-Jess

Here at the Rochester Falconcam we’re happy to be able to bring you high quality images and up-to-date information about Mariah, Kaver and their families each year. Most of the work that goes into producing the Falconcam is performed by dedicated volunteers, but we still have expenses for internet access, computer storage space, equipment maintenance and more.

We depend on the generosity of our viewers and merchandise sales at The Scrape for nearly all of our funding. You can help to ensure the future of the Rochester Falconcam, and have some fun all at the same time by joining our Pledge an Egg event!

Each year our viewers try to guess how many eggs Mariah will lay. We’ve seen her lay as few as 3 and as many as 6 eggs over the past decade. This year, why not turn the guessing into a fundraising event with “Pledge an Egg”!

How it works:
Pick a pledge amount for each egg. When Mariah has finished laying her eggs, probably around the middle of April, we’ll post the final tally here at Imprints. Multiply your pledge amount by the number of eggs and send in your donation. See how much money you can raise for the Rochester Falconcam! Ask your family, friends, co-workers or classmates to “Pledge an Egg”. Just download one of the handy pledge forms below to get started. On behalf of all of us here at the Rochester Falconcam, thank you for your generosity!

Pledge an Egg sign-up form (Portrait Orientation)

Pledge an Egg sign-up form (Landscape Orientation)

-Jess

It looks like Mariah produced egg #3 right around 4:10PM on the afternoon of April 2. That’s a little less than 56 hours after laying her second egg. She gave us our first clear view of all three eggs a few minutes later, as you can see from the time on the picture above.

Here’s another look courtesy of the Rochester Falconcam’s high-resolution Main camera. This is Mariah’s second year of “unpredictable” egg-laying times. We don’t like to deal in absolutes here at Imprints, but it looks like she may be establishing a new pattern in her golden years.

How many more eggs can we expect? That’s anyone’s guess. Watchers observed mating activity between Mariah and Kaver both in the morning and afternoon today, so we wouldn’t be surprised to see a couple more before the egg laying is done!

-Jess

Here at Imprints we receive a lot of questions from our readers. We’re glad to know there are so many curious people who want to know more about Mariah and Kaver, so keep the questions coming!

Now that Mariah’s in full egg-laying mode, I thought it would be a good time to address some of your questions related to reproduction. We covered some of this territory in last year’s posts on egg laying, and incubation and hatching, but you’re clever enough to have come up with some new questions, so here goes!

We’ve been asked many times about how long Mariah will continue to lay her eggs. After all, she’s been reproducing for 11 years now. So just how long is a Peregrine productive?

Well, that all depends on how long Mariah lives. Unlike human females, Peregrines don’t go through menopause. Once they reach reproductive maturity (typically in their second year), they can begin laying viable eggs, and they’ll continue to do so throughout their lives. Reproduction is one of the falcon’s strongest natural drives, and biologically speaking, it’s one of their primary functions. So, as long as Mariah is with us and has a mate and a suitable territory, we should be able to expect that she’ll continue to lay eggs and raise young.

It is true that as Peregrines age, they may not always lay viable eggs, but eggs can fail for a number of reasons that are not related to age. As we saw in 2006, injury may prevent the eggs from being properly incubated. In 2002, while Mariah was presumably in her reproductive prime, only 2 of her 4 eggs hatched. And last year, one of her five eggs mysteriously disappeared. Still, Peregrines in captivity have continued to lay eggs for as long as fifteen years or more, so we think Mariah still has many good years of motherhood left to her.

Another oft-asked question is: How does Mariah know how many eggs to lay?

Peregrines live a dangerous life. In the wild it takes nearly all of their energy, and a dose of good fortune to make their yearly migrations and return to their home territories to nest. Then they have to deal with availability of food, and external threats like predators and even other falcons who want to muscle in on their territory.

Fortunately, Peregrine females have evolved to take all of this into account during their nesting cycle. The lengthening of the day and warmer temperatures kick-starts their reproductive cycle by stimulating the release of hormones into their bodies. When falcons mate, fertilization of the ovum doesn’t take place right away. Instead, Mariah stores Kaver’s sperm until she’s ready to fertilize her eggs.

To figure out when she’s ready, she determines whether her environment is safe and free from stress, and how much food is available. If prey is plentiful and hunts are successful most of the time, she’s likely to lay more eggs than if food is difficult to come by. She probably doesn’t know the exact number of eggs to lay, but the average for Peregrines is 3-7, with 3 or 4 being typical. Believe it or not, forming the egg shells takes a lot of calcium out of her body, so the lack of calcium may trigger her to stop laying and begin incubating.

Finally, some of you have wondered about the fact that most of Mariah’s offspring have been female.

First a little background… WARNING: Science Alert!

At Harvard Univeristy back in 1973, a biologist named Trivers and a math whiz named Willard had a theory that the ratio of male to female offsping produced by a given pair of animals would tend to favor the sex that gave the best chance of future reproductive success (grandchildren and great-grandchildren) for the least additional investment of resources, that is, food and shelter (Whew– I ran out of breath writing that!). The Trivers/Willard Hypothosis was based on mammals, for which male offspring required more resources to produce. In mammals, healthy males are likely to produce many more offspring than unhealthy ones. So when times were good, mothers produced sons. Females, on the other hand, are likely to produce offspring even if they’re not in prime condition, so when the chips are down, it’s better to produce female offspring. The hypothesis is hard to prove, and many studies are inconclusive, but the theory seems to be generally well-regarded.

In Peregrines and other birds of prey, it is the females who are larger. They require more resources, but healthy female falcons are more likely to reproduce than unhealthy ones. In Australia, a couple of smart people named Penny Olsent and Andrew Cockburn actually studied Peregrines and other raptors using this hypothesis. They proposed a modified version of Trivers/Willard. It says that where prey is plentiful and the mother is healthy, more of her offspring would be females. At the Rochester site, we know that prey is very plentiful, and Mariah’s robustness is unquestioned. Combined with Kaver’s hunting prowess, it stands to reason that Mariah has all the resources she needs to produce the largest, most productive kind of offspring– daughters.

There you have it. A few more details about Peregrine reproduction.

-Jess

We hope you’ll join the Rochester Falconcam’s own June Summers and Jim Pisello as they talk about Mariah and Kaver on the 1370 Connection with host Bob Smith. The show will be broadcast live on WXXI AM 1370 radio at 12:30PM on Tuesday, April 1. And if you live outside of the Rochester area, not to worry! Listen to the simulcast on the Internet.

-Jess

Egg-citement reigns here at the Falconcam! At about 8:30 this morning, 106½ hours after laying her first egg, Mariah came through with number two. You can see the newest egg between her feet in the picture above, captured only a few minutes after it was laid.

Here’s another look at the two eggs. Mariah’s normal egg-laying interval of about 54 hours stretched last year to an average of over 70 hours, thanks to a long 106 hour period between eggs 2 & 3. Today’s longer interval equals the longest one she had last year. This may be due to her age, or it may be influenced by other factors.

Here’s a close-up of the eggs courtesy of the Rochester Falconcam’s zooming Camera 1. Peregrines normally lay an egg every 2-3 days, with the time between eggs getting longer as the falcon ages. We think Mariah’s at least 12 years old, so her advancing years could certainly explain these longer times. They might also have something to do with the recent battle for control of the nest box territory in which she and Kaver drove off an invading falcon. It’s impossible to say for sure, so we’ll just have to keep watching to see when her next egg will arrive!

-Jess

Rhea Mae, Mariah and Kaver’s daughter from 2006, has laid her first egg too!

Photo courtesy of Canadian Peregrine Foundation

In August of last year, Rhea Mae (on the left in the picture above) became the resident female at a nest site at the Sheraton hotel in downtown Toronto, Ontario Canada. She displaced the former female, named Wind, and established herself at the nest with Tiago, the resident male.

Linda Woods at the Canadian Peregrine Foundation took this picture of Rhea Mae and Tiago shortly after their egg was laid.

This is the best kind of news for everyone working to re-establish the Peregrine population in North America. Like Mariah’s son Freedom, Rhea Mae’s offspring continue an extraordinar lineage. We at the Rochester Falconcam are looking forward to following both Mariah and Rhea Mae’s families this year. The Canadian Peregrine Foundation has a website dedicated to Rhea Mae and Tiago. It features two webcam views. Check it out!

-Jess

At about 9:55 PM Eastern Daylight Time on March 26, Mariah laid her first egg of 2008! We’re glad to see that the recent territory battle doesn’t appear to have placed undue stress on the falcons.

Here’s a daylight picture of her with her first egg. Mariah generally lays her eggs at intervals of 50-55 hours, so egg #2 should come in the early morning hours of Saturday, March 29. Last year she surprised us with some longer egg laying times. Once, she went over 100 hours between eggs! So don’t be surprised if you don’t see a second egg when you wake up on Saturday, but keep watching! You never know when she’ll add another egg to the nest.

-Jess

On Easter Sunday, 23 March, some of our dedicated falcon watchers witnessed a territory battle at the nest box. When a non-resident female Peregrine flew into the area she was intercepted by Kaver. Long-time watcher and Rochester Falconcam team members Lisa McKeown and Carol Phillips observed several attacks by both Mariah and Kaver as they attempted to drive the intruder away.

Here is some of Carol’s reporting from the scene on Sunday:

…Kaver flew off of the tower, heading south. I watched him with my binoculars, until he met up with a bird past the communication tower. This bird was larger than Kaver and it was a PEREGRINE FALCON!

They both turned and started heading north towards the Kodak Tower! No matter how Kaver tried to push “The Intruder” away, she kept coming towards the tower. They were high above me. That’s when I spotted a 3rd Falcon, higher than the two battling above me! I quickly looked back at the tower and Mariah was up on the southeast corner of the launchpad, still sounding the alarm. I lost track of the 4th Falcon, but Kaver and the female (who has a large gap in her tail feathers) were coming closer and closer to the tower.

As you can read from Carol’s report, it appears there were a pair of intruding falcons, but the third one she mentioned never joined the territory fight and seems to have flown away. Mariah joined the attack and drove the female away from the tower toward downtown Rochester. She returned to the nest box and everything was quiet for a while, but the calm didn’t last. Again, Carol reports:

Alarm Kaking [sic] came from the tower. I quickly looked around, not spotting anything. Both Mariah and Kaver took off heading south. The Intruder was again heading in towards the tower. This time [they] were able to turn her around.

Unfortunately the intruding falcon came back for a third attempt. This time, the battle at the nest box lasted nearly an hour.

[Near 2:00 PM], all *#@%* broke loose. Again alarm Kaking [sic] from the tower. Again, [Mariah and Kaver] took off from the tower, speeding towards downtown! They were really far out before I was able to see their target. Both attacked in tandem, but the female was bound and determined to get to the tower. This time she would be successful!

In this picture you can see the intruder crouched in the south-east corner of the catwalk while Kaver watches alertly from the top of Camera 1. Shortly after this, Carol reported that Mariah actually climbed inside the iron bars of the catwalk and fought with the intruder. There was a lot of furious wing flapping and aggressive vocalizations before the intruding falcon finally decided that discretion was the better part of valor, and flew away. Here’s the final installment of Carol’s report:

I watched… as Mariah and Kaver followed behind the Intruder as she sped towards the tower. They passed over me, screaming. The Intruder landed on the east side playpen railing, I could just make her out. Kaver landed near the nest box and Mariah went inside the nest box. All was quiet for a moment.

Mariah came out of the nest box and flew around the tower. She was searching for the Intruder. It didn’t take her long to spot her. For a very long time (it seemed forever) both Mariah and Kaver took turns stooping on the playpen, where the Intruder had hunkered down… Finally Kaver settled on Camera #1 while Mariah continued the
attack.

Barb and Lisa had arrived during this attack and then Kathy O. We watched Mariah land on the south east corner of the playpen railing (base). At first it looked like she was resting. As we watched, Mariah spread her wings, like one of the fledglings mantling food.

We couldn’t see what had Mariah’s attention, but as we watched Mariah went through the bars and into the playpen. We
could hear horrible sounds of fighting inside the playpen. It seemed to last forever. Kaver watched from above on Camera #1. FINALLY, Mariah chased the Intruder out of the playpen and both she and Kaver chased her around the tower heading north this time. We all spread out in different directions, but none of us were able to see where they went. Thankfully it wasn’t long before first Mariah and then Kaver returned to the nest box area. Whew!

With Peregrine populations increasing thanks to successful reintroduction programs, territory battles are becoming more common. It’s an uncomfortable fact of life that there are more Peregrines than available nest sites, and as we’ve noted here before, the nest on the Kodak tower is an ideal site.

Mariah should begin laying her eggs any day now, according to her “normal” yearly schedule, but if she’s under stress or threat, she may delay laying them. If the threat is potent enough, she might not lay eggs at all. Since the intruding falcon hasn’t been seen since Sunday afternoon we’re hopeful that she has left the area for good, and that Mariah and Kaver will return to their normal routine. Everyone at the Rochester Falconcam will remain alert for further trouble and update you as soon as we know anything. Our sincere thanks go to Carol, Lisa, and all of the others who gave up their Easter Sunday afternoon to observe and report on the scuffle over the skies of Rochester.

-Jess

UPDATE! 22 March 2008- Scroll to the bottom for a picture of Freedom’s new mate!

Rochester Falconcam team member Carol Phillips has received information from Doug, one of Freedom’s caretakers at his nest site in Port Colborne, Ontario Canada. Doug writes:

I just thought you should know that Freedom appears to have a new mate. The resident female here in Port Colborne “Purity” left in the fall. We think she may have migrated (for the 1st time). I’m sure I saw her back on Feb. 19^th but have not seen her since. There is a new girl on the block here. She is a [juvenile] produced in Mississauga Ontario in 2007. Her name is Millie (same name as one of Freedom’s 1st offspring!). This bird has been here the entire winter. Freedom & Millie are exhibiting courtship behaviours. Since Millie is so young, we’re not sure if they will be able to have a clutch this year or not. We do have our fingers crossed though. If things change, I will let you guys know.

This is very surprising, unexpected news indeed! It would be unusual for an adult female to be driven away by a juvenile, unless the adult were very old or injured in some way. Since Purity is unbanded, her age is undetermined. Any guesses about why she was replaced by Millie would be pure speculation, so we’ll just wait to see what we can learn.

We’re working on getting more information about Millie (and hopefully a picture or two of her) from our friends at the Canadian Peregrine Foundation. We’ll be sure to bring all the news to you as soon as we receive it.

UPDATE! 22 March 2008
We’ve recently received this picture of Millie from Doug, one of Freedom’s caretakers at his Port Colbourne nest site!

Thanks Doug and Carol for the update!

-Jess