Prothonotary Warbler box 300-2 First attempt of 2010

May 24th, 2010

I am pretty excited tonight.  I had my first prothonotary warbler of the season hatch this evening.      We have had quite a bit of rain and flooding this spring.    I have a low-lying field on my farm that is surrounded by a big loop of a  creek that becomes a small river when it floods.   We live just south of the Missouri River and the river backs up into “Meadow Creek”  with any flooding.     I have several boxes right along the edge of the creek that end up looking like I placed them in a pond when the flooding occurs.       The most recent flood waters finally went down enough that I could pull on my mud boots and make my monitoring rounds in the flood zone.     Sometimes I use a jon boat when it is flooded, but I did not have time with this most recent flood.    I saw prothonotary warblers fly from three of the boxes and one had a hatchling that looks like he probably just hatched today.     This was an interesting nesting attempt in that it started out with what appeared to be a house wren dummy stick nest.    I usually clear out stick nests, but leave them if there is an actual cup nest.   This nest had moss and leaves and bark strips that I do not usually see with house wrens.        I was hoping it was a prothonotary warbler and my hopes were fulfilled tonight.   They are such wonderful little birds.

Gilbertson nest box near creek.

This is one of my Gilbertson PVC boxes.   Notice the creek at normal low levels in the background.      Also check out the dead cottonwood tree snag with the natural cavity in the background.   I leave as many of these up as I can.     I have made several modifications to the basic Gilbertson box.    I have attached some corrugated plastic to the top and back of the box.  On the very top of the roof I have placed a 12 by 12 inch shingle.      There are rubber flaps on the sides and front to provide more shade and general protection from the elements and the flap in front is intended to cut down on  predation from anything trying to reach into the box from above.    The theory is that a predator would have to reach around this or if it pushes down on it, it will cover up the entrance hole.    I am hoping that Bet Zimmerman notices this and I have the “Dodson Flap” named after me and added to the list of predator guards on the Sialis website.     I offer absolutely no evidence that it actually does anything to benefit the birds, but this does prove that birds will at least use a box despite my alterations.     This flap may be my one shot  at fame.    I have been practicing medicine for a couple of decades now and I have not managed to discover a new disease or a new cure for an existing disease in that whole time!   I don’t see a Nobel prize for medicine in my future…But I digress……

Nest noted May 2, 2010

This is the nest as it appeared on May 2, 2010.   As I approached the box, I saw big sticks protruding from the entrance hole.    This may be the first time I had a nest with a stick foundation lead to anything other than a house wren brood.   There are certainly plenty of house wrens in the area and they have pecked my prothonotary eggs in the past.    Not this time.  (At least not yet).

Dropping flood waters

This is how the box looked tonight (May 24, 2010) as the flood waters were dropping.    Small pieces of driftwood had piled up around the base of the box.    Luckily, since the flood waters are mostly backwater from the nearby Missouri River, there really is not much current when it floods.   Things drift in and catch on things, but I have never had one of my boxes actually be washed away.   I had to slop through about 20 yards of shallow water and mud to get to this box.    I whistled the tune to the first line of “We Three Kings of Orient Are”  as I approached the box.  I always do that.   I do not know if the birds figure out that is “my” call, but it is just a habit I have gotten into.    As I whistled, a female prothonotary flew out and landed on a nearby branch.   She really did not seem too worried.   Perhaps she remembers me from a previous years nesting.

Prothonotary hatchling May 24th, 2010

(or so I thought….    read on)

This is what I saw when I opened the box.     This guy was begging for food.   I took a quick picture and left the area so mom could feed him.

I will post updates and try to get some pictures of the adults over the next couple of weeks.   I am still trying to figure out how to do this whole “blog”  thing.   Do I wait until a nesting attempt is complete and then post?   Do I do I update existing posts?   Advice is welcome.

Update May 25th, 2010

More hatchlings. May 25th, 2010

I slopped through the mud again to see if the remaining eggs hatched.    The last chick was working on breaking out of the egg when I opened the box.   Notice  how huge the biggest chick looks compared to the others.   Did he grow that much in one day or perhaps did he hatch before yesterday?   I have no way of knowing for sure.      All of these pictures so far have been taken with a little point and shoot camera.    I hope that it dries up enough that I can take my “big” camera  and tripod down by the creek and get some pictures of mom and dad soon.

Update May 26

May 26th

May 26th

I am not sure if there are five or six birds here.      There is the one unmistakable “monster chick” and at least 4 others.    The base of the pole is no longer under water, but it is still very muddy.      There are quite a few ants in the area.  They were swarming a nearby nest box with only a dummy wren nest in it.    I put some boric acid at the base of  this pole and sprayed some pyrethrin spray on the pole and into the top of the stovepipe baffle.    Hopefully that will keep the ants at bay.    In the past, I have used tanglefoot, but I do not like using it when I am also handling my camera.    That is just asking for trouble.    I am still amazed how much bigger the one chick is compared to the others.   The color of the inside of the mouth seems different as well.    I just assumed it hatched a day or two earlier.    I guess that I should consider the possibility that an egg was “dumped” into the nest by another bird.

Update May 27th

As I slept on this overnight, I began to worry more and more that the “monster chick” might be a cowbird.    These are “obligatory brood parasites”  meaning that they are birds that do not make nests, but lay their eggs in the nests of other birds.      Bet Zimmerman has a nice post on them here….

I posted a question to “Bluebird L”   which is a listserve run by Cornell that allows me to post questions to experts all across the country.   (This listserve is being shut down tomorrow, but that is a whole different story)    Keith Kridler is a living legend in the bluebirding world.      He has co-authored the definitive book on bluebird monitoring  and was kind enough to drive all of the way from Texas to be the keynote speaker for the first Missouri Bluebird Society conference.    He is great.     He  posted a couple of emails which he gave me permission to share.   The bottom line is that the chick that I so proudly presented to the internet as my first prothonotary warbler chick of the year is in fact a cowbird.

Emails from Keith Kridler:

Bet has some photos I took of a Brown Headed Cowbird chick in a Carolina Wren nest a few years ago. This one happened to be in a Gilwood nestbox. Depending on the size of the female Brown Headed Cowbird I have had them remove bluebird eggs from nestboxes with 1&1/2″ round entrance holes and then lay eggs in these boxes.

One of the identifiers of the cowbird chick is the light or almost white colored down or fluff when just hatched. (Many other young bird species are also light colored!) The other is the bright crimson red well maybe Raspberry red lining to the inside of the mouth. The brighter the red color inside the mouth the more this is supposed to trigger the adults to feed
this chick as compared to the rest of the chicks with an orange or yellow mouth lining. (Earlier this morning I mentioned Mammals don’t see red light very well:-))

Also if you wait a few days the cowbird chick will be able to open it’s eyes days ahead of the warbler chicks and then it will actively reach towards the adults as they enter the nest and the cowbird chick will eat all the food it wants. These cowbirds also stand on top of the other young birds in the nest with it effectively holding them down and starving them or crushing the life out of them.

This is where IF you had a nest of House Sparrows you could move this chick and give it to the House Sparrows to raise:-)) Anyway I think Bet has a series of photos showing the Brown Headed Cowbirds and the color of their mouth. I would go back and whistle and get photos of this as it might be years before you experience this again. On the OTHER hand this female MIGHT hit a LOT more of your nestboxes over the next few weeks. They are reported to lay upwards of 40 eggs in other bird nests per nesting season…. Some species of birds synchronize egg laying in a colony or area making it harder for a cowbird to lay eggs in all the nests available in her territory. Keith
Kridler Mt. Pleasant, Texas


I finally found Jack’s photos on-line and YES this is a baby Brown Headed Cowbird. Notice that at just day three or four the Cowbird baby has it’s eyes open. If you whistle or squeak you can get a shot of just how much higher up this bird will reach as compared to the warblers. While you are
whistling or squeaking you can now move your finger over and near the cowbird baby and it should now be able to “go after” your finger as it is programmed to target and follow the adults coming to feed the nestlings thus getting most or all of the food. It all depends on how fast the adults can bring in food as to whether or not all of the young birds will starve except for the cowbird. The warblers will also have to stay out from under it’s feet.

Notice in these photos that the actual opening for the eye is fairly small BUT you can see the entire eyeball of these baby birds. If you look closely you will see that the size of their two eyes is actually going to be larger than their “bird brain”. Humans on the other hand have relatively small sized eyes as compared to our brain size.

I removed a baby cowbird like this one that was so much bigger than the baby bluebirds it was dumped in with and moved it to another bluebird nest with young larger than the baby cowbird. Three hours later the adult bluebirds had REMOVED this one baby cowbird so they recognized it was different from their chicks! Keith Kridler Mt. Pleasant, Texas

I had done all of this correspondence from work.    When I got home, I checked out the box again.    I think that even without expert help, I probably would have guessed that the “monster chick” was a cowbird based on the size and appearance difference tonight.

Cowbird and Prothonotary Warblers May 27th

An idea struck me and I went back up to the house, got a spare Gilbertson PVC box and then got what I think is a dummy prothonotary nest that has been sitting unused for over a month.   I did a little tinkering and the result was the Dodson/Gilbertson Duplex.   I think we will call it the “DGD”.

Gilbertson Duplex May 27th

The cowbird was transferred to the second Gilbertson and the Prothonotary warblers were left in the original nest box.

Transplanted Cowbird

Prothonotary Warblers without the Cowbird

I fed the Cowbird some mealworms and set up a mealworm feeder a short distance away to help out the Prothonotary parents.         We will see what happens.     I am not sure this solution was entirely legal, but it is the best that I could think of.    If I am arrested I will ask for a jury of my peers (other bluebirders) and throw myself at their mercy.

Mealworms to help out parents in their feeding efforts.

Update May 29th

Libby monitoring the duplex.

Well, we are a day and a half into project duplex and so far so good.     My 13 year old daughter Libby is helping me monitor.   Of course she wanted to adopt the cowbird and bring it to the house, but we are sticking with my original plan.    We appear to have 4 viable prothonotary warbler chicks and one cowbird chick hanging in there.

Cowbird chick May 29th

Cowbird chick May 29th

Prothonotary Warbler Chicks May 29th

I spent a little time this morning observing from a distance and the Prothonotary parents are definitely bringing food to both boxes.    It has also dried out enough that I was able to bring down my “real” camera with a tripod and long lens.    The lighting was not great, but I was able to snap a few pictures of the adults.

Adult Prothonotary Warbler bringing food to Cowbird chick in second box.

Adult Prothonotary Warbler with food

The adults seem to be having no trouble finding food.   They really have not shown much interest in the mealworms that I have offered.

So far so good.      I will keep you posted.

Update June 1, 2010

When I checked the boxes yesterday the cowbird’s box was empty.   I do not know if his adoptive parents rejected him or something else got him.      The  four prothonotary chicks were fine.    I would think that if a raccoon or snake had been the culprit that they would be missing too.    My main goal was to protect the prothonotary warbler chicks, but I was really hoping that the “duplex”  idea would give the cowbird a chance and it really seemed to be working.    Cowbirds are clearly not my favorite birds, but I still felt a sense of loss when I opened the box and found it empty.

I will continue to post pictures of the prothonotary chicks every few days until they fledge (or disappear).

Update June 2, 2010

The prothonotary chicks continue to grow.   One week old now.

Prothonotary Warbler chicks June 2, 2010

Update June 4, 2010

Prothonotary Chicks June 4, 2010

I think they may be getting close to fledging.   Prothonotary warblers usually fledge less than 2 weeks after hatching.    Sometimes in as little as 9-10 days.

Box 300-2

After the cowbird chick disappeared, I removed the attached second Gilbertson box.    The creek is back up a bit, but the base of the pole is not under water.     I sprinkle a bit of “snake away”  and “ortho home defense max”  granules at the base of the pole to discourage snakes and ants.      I hope it is working.

Update June 4, 2010

Only one chick left. June 5, 2010

I am assuming (hoping) that the others fledged already.

Update June 5, 2010

Empty nest. June 5, 2010

Well, this has been an interesting nesting for me.     House wren stick nest to Prothonotary nest  to cowbird parasitism  to what I hope was successful fledging of four Prothonotary Warbler chicks.     Throw in some flooding for added interest and it was a pretty eventful nesting.      Thanks to all who commented and offered advice both here and on Bluebird L and Yahoo Bluebird monitors group.

This entry was posted in Birds, Bluebird Trail 2010, Cowbird, Nesting attempts, Prothonotary Warbler and tagged , , . Bookmark the permalink.

10 Responses to Prothonotary Warbler box 300-2 First attempt of 2010

  1. Steve White says:

    Jack – Thanks for sharing your nesting experience with the prothonotary warbler. Been thinking about putting up a few boxes for them on our farm (84 acres). We have a creek that runs through a small stretch of timber. Only about 2 ft deep in most places but like yours, can get out of it’s bank when it floods. Can you give me an idea of box dimensions for the warbler and any other special things that I need to consider when placing the box. Much appreciated!

    Steve @ ’bout Broke Farm
    Vermont IL

    • jackdodson says:

      The box in this post is a Gilbertson PVC box. It is actually designed for bluebirds, but the prothonotary warblers really seem to like it. I order them directly from Steve Gilbertson
      These boxes are considered by some to be too small for bluebirds, but I have bluebirds and tree swallows choose and successfully use them regularly. The floor of the box is 4 inches in diameter, so only about 12.5 square inches of floor space. The entrance hole is 1.5 inches in diameter, but the prothonotary warblers can fit into a smaller hole, I have had them use a box with a 1.25 inch metal hole restrictor.

      Bet Zimmerman has collected a lot of information on these birds. Link is below…

      Some people actually place the boxes above water. I place mine along the creek, but have had them use a box all the way up on top of a ridge/bluff above the creek.

      I hope this helps.
      Jack Dodson

  2. Tena Taylor says:

    I too have my first prothonotary warbler nest & baby. When we cleaned out our martin gourds, we replaced one, and hung the one we removed on the fence by our shop. Not a very good location – too close to the ground and totally unprotected. As I walked by last week, the prothonotary warbler flew out. There was only one egg in the nest. Yesterday I peeped in and noticed that egg has hatched. The little mama is taking good care of that one baby. Hoping all goes well in that not perfect location. Is it unusual for there to be only one egg?

    • jackdodson says:

      Usually there are more eggs, typically about 4-6 on my trail. Perhaps something happened to the others. Good luck. Jack

  3. Bet says:

    Fantastic photos Jack! Thanks so much for sharing

    Bet from CT

  4. Gail Storm says:

    Those photos you took tell a great story! I’ve not had the experience of a cowbird in with my bluebirds but I have seen them with other songbird species around here. The parents bring the fledged baby to our feeders to feed it and it’s HUGE compared to some of the parents. I love your idea of seeing if they will take care of 2 nests. Interesting test of bird instinct. Keep us updated, no matter the outcome.

  5. Jean says:

    Outstanding photos and story. I have learned much from this post. Never knew a Cowbird would enter a nestbox.

  6. Chris Burney says:

    Nice story- thanks for sharing! We are about to implement our own Nest Box Program for PROWs on our conservation lands, and this account was very enlightening.

  7. Derek Burdon says:

    A heartwarming story. I carve birds for fun and competition .IAm planning on doing a PW with its mouth open singing and I cannot find any pictures of the inside of the mouth or the color.Can anyone help me? Thanks in advance.

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