Mar 30 2010

What’s happening at the Gulf Tower?

Published by at 7:12 am under Peregrines

That’s the question all the peregrine watchers are asking.

It’s been ten days since Dori won the Gulf Tower site from the previous female resident, Tasha, and eleven days since Tasha laid her last egg. 

For a while neither Louie nor Dori did anything with the old eggs except court and bow over them.  Sometimes Dori pushed them out of the scrape.  Later Louie would push them back in. 

Then over the weekend Louie started incubating Tasha’s eggs for an hour or two at a time.  As is typical for male peregrines, he didn’t incubate them overnight but he showed up when expected — at dawn and early afternoon — as if he was taking his normal incubation duty shift.  Dori didn’t participate. 

This puzzled everyone.  Are Louie and Dori disagreeing about the eggs?  Will Dori refuse to lay her own if the old ones are present?  Are the old eggs viable?  Will Louie eventually give up on them?  Will Dori eventually adopt them?

As much as this seems a drama to us, something very simple is going on.  Louie and Dori are at different stages in the nesting sequence.  He has eggs, she doesn’t.  When she lays eggs she’ll catch up to him.

Keep in mind this couple has known each other for only ten days.  If their courtship goes well — and that appears to be the case — Dori’s hormones will trigger egg laying.  She can’t “refuse” to lay eggs.  She won’t have any choice about it, and she’ll have to put them somewhere.  The only thing she could possibly refuse is the ledge where her rival nested, but she hasn’t done that.  She courts at the nestbox, she rearranges the gravel and she digs at the scrape where the old eggs were laid.  Dori will lay eggs when she’s ready.

Humans are impatient during a slow drama like this one.  Watching the webcams is a lot like watching television where we expect the action to unfold a lot faster.  But remember, the nature programs leave out all the boring bits.  They have only an hour to show you a whole year of a bird’s life.

Give this pair some time.  Nature is taking its course.

p.s. The old eggs might not be viable.  If so, the adults will move them away if they don’t hatch.

(photo of Louie from the National Aviary webcam at Gulf Tower.  Thanks to Traci Darin for the screen capture.)

38 responses so far

38 Responses to “What’s happening at the Gulf Tower?”

  1. faith Cornellon 30 Mar 2010 at 9:22 am

    Yes we are not a waiting population; instant everything. I still cannot access cameras altho I get to site & it tells me how many other people are watching. Did everything everyone told me; left msgs with aviary people; hope they get back to me. So I will access this site. Have tried from all other places to get in. Frustrating. Because the old system worked just fine with me. I am too old for change. But an enjoying this new drama thru your words & pictures. Faith Cornell

  2. Marianneon 30 Mar 2010 at 9:38 am

    Thanks for the update. So many questions we had. It seems like a complicated scenario!

  3. Patsyon 30 Mar 2010 at 9:44 am

    Kate, thanks for the insight.

  4. Joannon 30 Mar 2010 at 10:24 am

    Kate, Thanks for explaining what is going on with Dori & Louie as well as the eggs. I guess we are an “instant” generation wanting everything to happen quickly.

  5. Carlana Rhotenon 30 Mar 2010 at 11:35 am

    Thanks for a wonderful, informative web site. Are schools regularly notified to take advantage of it?

    I hit the panic button this weekend when I did not see Dorothy relieve U2 for two days and there was a lot of unusual noises . On two occasions I saw a female enter the nest, without any interest in sitting on the eggs. I jumped to the conclusion that Dorothy had been done in and a new female was courting E2.

    Anyway, Monday and Tuesday, Dorothy is back to her schedule of relieving U2 around 9:30 -10 am. so I was all wet.

    I really appreciate the close-up of their eyes, so beautiful. Here are two versions of an old poem that might appeal to falcon people. “How exquisitely jeweled, this talon that pierces the heart” OR “How exquisite, this jeweled talon, piercing my heart.” Re write it to suit yourself. CR

  6. Kate St. Johnon 30 Mar 2010 at 12:28 pm

    Carlana, from your comment I think there’s some confusion about which nest is which and which individual birds are at each site.

    The nests certainly do look similar on camera. Here are some tips on telling the difference between the 2 nests:

    First, always looks at the top of the camera view to see the name of the nest: Cathedral of Learning or Gulf Tower. Sometimes that’s the only way you can keep them straight.

    The Cathedral of Learning pair is Dorothy and E2. They have 5 eggs and are almost always sitting on them. The camera at the Cathedral of Learning always looks down on the peregrines because the camera is mounted quite close. When the birds are not on the eggs, the eggs are very easy to see and count.
    Dorothy stays on the eggs all night and most of the day. E2 (the male) usually gives her a break and sits on the eggs just after dawn and in the early afternoon.

    The Gulf Tower pair used to be Tasha and Louie but since March 20 it has been Dori (new female) and Louie. At the Gulf Tower the camera looks straight across at the birds, nearly at the level of the gravel. When the camera is in its normal position (zoomed back), the eggs are hard to see and count. As of today (March 30) the peregrines at this site are not usually sitting on the eggs.

    Hope this helps.

  7. Joannon 30 Mar 2010 at 12:43 pm

    At the Gulf Tower It looks like Tasha’s 2 eggs have been moved out of the scrape where they were laying & I see 1 egg in that same scrape at 12:42 PM 3/30/10. Possibly Dorie has laid her first egg?

  8. Kathy McCharenon 30 Mar 2010 at 12:56 pm

    Kate–I may be the only person watching who doesn’t know this but could you explain the peregrine mating process? Do the continuing courtship bows mean that Dori and Louie have not already mated? If not, will the bows stop after they mate? If they have, how much time must pass before Dori will begin laying her eggs? Will they mate more than once? (once for each egg?) Thanks for tending to the falcons and to your human flock of peregrine lovers!

  9. Kate St. Johnon 30 Mar 2010 at 1:50 pm

    Peregrines strengthen their pair bond in many ways, most of which you will never see on the webcams. A huge part of courtship consists of aerial displays — that’s what hooked me on peregrines. They fly alone above the site (I think of it as showing off) and fly together to cement their pair bond. They circle high, dive and roll, play at stooping, hunt cooperatively and do food transfers in the air. Copulation is usually in some prominent location, not at the nest scrape. (Example: Beauty mating on the Mercury statue in Rochester, NY.)

    Ledge displays are only one piece of the picture and aren’t enough to tell how far the couple has come on the path to mating. Those who watch from the street downtown could tell us a lot more than we can tell from the webcam.

    Here’s some info on peregrine mating from an excellent source, Cornell Lab’s Birds of North American Online: “Completed copulations begin at least 2 wk prior to egg-laying. Duration of completed copulations ranges from about 5 s, earlier in season up to 10 s; normally conducted in close proximity to nest ledge. Copulations continue until third egg laid.”

    If you are interested in bird biology, get a subscription to Birds of North American Online here:

  10. Carlana Rhotenon 30 Mar 2010 at 1:51 pm

    Dear Kate,

    I appreciate your explanation about the two nests, but I was not at all confused about that. I may have been getting U2 and Dorothy mixed up, bur I did not have the nests mixed up.

    I have a baby monitor, that I can listen to c-span from any place in the house. It is also near the computer, so I can listen for falcon noises and get to the screen to see what is happening, when they are making noise.

    I consider myself to be completely ignorant about falcons. It was just that I watched a week of Dorothy relieving U2 in the morning, usually between 9:30 to 10 am.

    Sat and Sun broke the pattern, plus a lot of falcon noises off screen, plus a female coming on screen twice on Sunday without sitting on the eggs. After your great story about the saga of poor Tasha, I was ready to believe that the strange behavior was due to a strange bird.

    I am going to try and keep my checking on the falcons to once a day for 5 minutes in the future. They are so beautiful, it is easy to fall in love. CR

  11. Kate St. Johnon 30 Mar 2010 at 1:56 pm

    Thanks, Carlana. I’m glad you were watching. They are certainly easy to love — and they’re addictive. Fortunately nothing bad has happened at the Cathedral of Learning nest.

  12. Kathy McCharenon 30 Mar 2010 at 2:02 pm

    Thanks so much for the information, Kate. And for the link…

  13. Martinon 30 Mar 2010 at 4:07 pm

    Thanks for clearing that up, I thought thats what was going on, what Im wondering now is, if Dori makes her own scrape in the same nest and lays her eggs in it ,which eggs will Louie incubate..

  14. Kate St. Johnon 30 Mar 2010 at 4:29 pm

    Interesting. We’ll have to wait and see.

  15. Cory DeSteinon 30 Mar 2010 at 4:35 pm

    Has any birders have any confirmed sightings of Tasha lately?

  16. Katie Con 30 Mar 2010 at 5:12 pm

    Hey Kate,

    I have a question for you. Could you please post profiles of each peregrine with some distinctive marks highlighted? I love watching the videos, but I can never tell who I’m looking at. Dori? Louie? Since I watch the Cathedral during the day, I assume I’m looking at Dorothy, but any clues – maybe a Who’s Who of Pittsburgh Peregrines with Pictures – would be really helpful.

    Keep up the good work! I love this blog, it’s really awesome. Way to go!

  17. myontzon 30 Mar 2010 at 7:26 pm

    Yes, Martin that is very interesting!!! Let’s hope that Dori make the decision for him and lays her eggs in the same scrape. hahaha

    Thanks Kate for sharing all your knowledge with us! Your post did clear up a lot of my questions. Thanks again!!!

  18. Tracion 30 Mar 2010 at 11:22 pm

    For Faith –
    Make sure you have all the updates for your operating system. Also, make sure you diasble any pop-up blockers – as that might be preventing the connection from completing.

    Once I upgraded my version of flashplayer I’ve been able to view all of the sites without any issues.

    I hope this both makes sense and helps. It must be so frustrating to not be able to see any of this. 🙁

  19. Kate St. Johnon 31 Mar 2010 at 7:54 am

    I’ve updated the Peregrine FAQs and added “Incubation ” in the Nests and Eggs section to help you figure out who’s who on camera. Also, in the Appearance and Behavior section there’s a “Who’s Who at Pitt?”

  20. faith Cornellon 31 Mar 2010 at 8:31 am

    To everyone who addressed by inability to access the new camera system. This AM ist is up & running for me. I put in all programs suggested by Kate & the director at the Aviary & you watchers, like flash player, Foxfire, enabled Java, my poor old computer probably thought it was being taken over by aliens but all is well & I can become compulsive again watching these wonderful creatures. Faith Cornell

  21. Katie Con 31 Mar 2010 at 8:38 am

    Thank you for your response! I really appreciate it. It is possible to tell the difference between Louie and Dori yet, or is she too new to have discovered any obvious differences yet?

    Also, why is the Cathedral of Learning cam so zoomed in? Doesn’t it normally have a wider angle of view?

    Thanks again!

  22. Kate St. Johnon 31 Mar 2010 at 9:28 am

    Yay, Faith!

  23. Kate St. Johnon 31 Mar 2010 at 9:29 am

    The Pitt camera was zoomed in by PixController. It can zoom out a bit to show the whole nest but not as far back at the Gulf Tower camera.

    I haven’t got pictures yet of the difference between Dori & Louie. It sometimes takes a long time to get pictures in the same pose.

  24. Tracion 31 Mar 2010 at 10:29 am

    Dori has two small white splashes of feathers on her upper wings. This is how I notieced that she wasn’t Tasha. Louie does not have these but rather a splash of white feathers across his upper back.
    I’ll see if I’ve managed tocapture any of this on the web captures I have that show this and email them to Kate.
    For me, it’s easier to tell the difference between Dori and Louie than it is E2 and Dorothy!!

  25. Gloriaon 31 Mar 2010 at 11:51 am

    Dori was at the GT this morning standing to the (camera left) of the eggs for quite some time… I was hoping for an egg, but she left after “puttering” around and eating some rocks (at least it looked that way)…. Louie’s there now sitting on Tasha’s eggs… guess we’ll have to stay tuned!!!!

  26. Dora Clavell-Powerson 31 Mar 2010 at 11:56 am

    I am very grateful for your time and efforts to keep us updated. I work for an elementary school and many of the teachers/students have taken the falcons “under their wings”……..for many , having this “up close and personal” view of nature is beyond words!!! The students are anxious to see when the hatching begins… do I !!! Gracias

  27. Pat Lawrenceon 31 Mar 2010 at 12:41 pm

    Can the eggs be removed by the authorities so they can start afresh? I don’t blame Dori for not wanting to lay on someones elses eggs!!

  28. Kate St. Johnon 31 Mar 2010 at 1:01 pm

    There is no need to remove the eggs. In peregrines “completed copulations begin at least 2 wk prior to egg-laying” (see note above), so it may be about two weeks from the time Louie and Dori started mating (earliest would have been March 20) until the point at which she lays an egg.

    Dori likes the nest box. She has been digging scrapes and squatting over them. She might lay her eggs where the old eggs are or she might lay them in one of the other scrapes (the bowl-shaped depressions she’s been digging). Either is fine.

  29. John Englishon 31 Mar 2010 at 7:55 pm

    I access the cams via
    I still can’t reach them via WildEarth.

  30. Suzanneon 01 Apr 2010 at 10:42 am

    Now that Tasha does not have a nest, what if she has another egg to lay?

  31. Kate St. Johnon 01 Apr 2010 at 11:33 am

    Don’t know, but chances are very good that she doesn’t have another egg to lay.

  32. Pat Lawrenceon 01 Apr 2010 at 3:23 pm

    Am I correct in seeing two (2) eggs at the Gulf Tower yet on the web page it only lists as March 17th 1st egg. I had noticed this phenomenon for a few days now. Are they discolored because they are not being incubated correctly?

  33. Kate St. Johnon 01 Apr 2010 at 3:33 pm

    There have been 2 eggs at Gulf Tower since Mar 19. The Aviary web page was not updated with “2nd egg” because by the time it would have been announced, Tasha was gone and Dori was in her place (that happened on Mar 20).

    One of the old eggs is very red-brown, the other has white blotches. They were each that color from the start. Incubation is unlikely to affect their color that dramatically. Here’s more information on peregrine egg color:

  34. Kate St. Johnon 02 Apr 2010 at 8:40 am

    Today’s Post-Gazette has an article about the Gulf Tower peregrines here:

  35. jlwon 02 Apr 2010 at 9:41 am

    is it my imagination, or are there 3 eggs in the GT nest this morning? it’s hard to tell – the falcons have pushed the eggs together. but it looks to me like there might be a third (brown) egg sitting between the light and dark eggs.

  36. Jennieon 02 Apr 2010 at 10:49 pm

    April 2, 10:47 p.m. Dori just laid an egg next to Tasha’s eggs.

  37. Jennieon 02 Apr 2010 at 10:57 pm

    10:57 p.m. she finally moved so that you can see all three eggs.

  38. Michellineon 02 Apr 2010 at 11:16 pm

    Dori just laid her first egg! 10:45 Eastern. Next to Tasha’s eggs.

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