Prothonotary Warbler Project – Continued

Readers:  Thanks so much for reading the previous article about this project and for expressing your desire to know more about what we’re doing and how we’re doing it. Using a series of photos accumulated thus far over the past six weeks of monitoring the nest boxes, I will give you a more in-depth look and a better understanding of those things.

BTNEP’s Prothonotary Warbler Conservation and Monitoring project is done in partnership with the Prothonotary Warbler Working Group, which is a consortium of federal and state agencies, NGOs, and universities to meet the needs of this declining warbler species.  Through this work, we strive to

  • Identify and fill knowledge gaps in the breeding, wintering, and migratory ecology of this species.
  • Measure vital rates and better understand the full life-cycle dynamics to quantify threats and identify factors that limit population growth
  • Develop a conservation plan and implement conservation actions that reverse population declines 

As mentioned in the previous article, we installed 50 nest boxes in two locations:  Lake Palourde area near Morgan City, LA and within the Mandalay National Wildlife Refuge near Houma, LA.   Since that May article, we have banded 61 birds, including many of the mother birds and most of the babies.

That seems so incredible to me, because the timeline is so short in which all of this happens.  After the nest is complete, the female lays one egg per day until the clutch is complete, with the average clutch size being 3-6 eggs.  She then incubates them for about 12-14 days.  Both parents feed the nestlings during the 10-11 days it takes for them to “fledge”, (learn to fly).  Each nesting pair typically has up to two broods in its southern breeding range. (Three broods isn’t typical but can happen in the south). By August, these PW families will be on their way back to their southern wintering grounds.

Now, let’s take a look at the process of this data-gathering journey thus far.

Ideally, we capture the female inside the nest box while she’s either sitting on the eggs or the new-born chicks.  We must approach very quietly and in stealth mode, which isn’t easy on the water. From the front of the boat, Natalie advances using the trolling motor.  Once she’s close to the box, I drop the anchor and use the rope to stop the bow of the boat just in line with the nest box while Natalie places her net over the front opening, taps the box, causing the female to fly into the net; that is, if we’ve been successful in our silent approach. (For the most part this approach has worked very well, but I must admit that there are still a couple of wily females out there that heard us coming and flew out before we got close!)

With equipment at the ready, Natalie takes the next band in the sequence and records its correlating number.  That number is later recorded in an online database which allows for reporting and tracking of each bird if they are caught in the future.  This information is helpful in determining nest site fidelity, survival rate, life-span, and migratory pathways. Using a tool that resembles pliers, Natalie carefully applies the band around the female’s leg and then confirms the number on the band with the written record.

Natalie then starts her assessment of the female bird and data gathering.  The data gathered includes cloacal protuberance (males) or brood patch condition (females), body fat, body molt, flight feather molt, flight feather wear, molt limits, wing chord measurement, age, weight, nest box ID. In addition, she closely observes the feathers for coloring, condition, and color patterns on the tail and wing feathers; all of which indicate whether this is a first-year breeding or older female.  

She then gently places the bird in a cotton draw-string pouch, which she previously weighed, and places it on the digital scale.  After recording the weight, it’s time to check and record the overall health of the bird and gather feathers from the crown, chest, wing, and tail and seal those in an envelope to be later sent to a consortium partner. 

After all the assessments are completed and recorded, Natalie then takes a few quick photos and lets the bird fly away.  Next, we check to see what surprises wait inside the nest box.  

If the nest holds eggs, she counts them and observes the overall condition of the nest and makes note of those things. If there are chicks in the nest, Natalie first determines the age of the chicks by the overall size and the extent of feather development. If they are between five and eights days old, they can be safely banded.

Using a little bowl lined with a cotton cloth, Natalie gently removes all but one of the babies from the nest.  She always leaves one baby on the nest because the mother and father are actively feeding them, and an empty nest might upset them enough to cause them to abandon the nest.  We certainly don’t want that to happen.      

First, the chick is weighed. Next, Natalie uses a leg gauge in order to make sure the band will fit comfortably.  Note that the bands aren’t dangerous, because as the chicks grow, the leg gets thinner, not thicker, which enables the band to be worn comfortably.  She carefully applies the band around the leg, double-checking its ID with her notes, and the chicks are then returned to the nest. Lastly, the one remaining chick receives the same treatment.  Using either the trolling motor or a paddle, we slowly back away from the nest box and continue about 100 meters to the next one, until we’ve checked them all.

With only a few weeks left in this project, we currently have a couple of nests with eggs or babies in them, so we will be checking weekly for hatching, banding, and then fledging.  After all the nestlings have fledged, we will then clean out the boxes and secure them for winter, to be uncovered and readied for the 2018 spring migration.  

The things that have most impressed me during this process include Natalie’s meticulous methods, attention to detail, and her sheer love of and concern for these beautiful winged creatures.  Secondly, I’ve been impressed with the dedication of these PW parents.  My favorite moments have been while anchored within feet of the nest box, both parents continued bringing food to the box to feed the remaining nestling.  Some of PW couples were put off by our presence, making that known by a chip-chip warning sound, but many of them flew right into the box within feet of us. It was, indeed, magical–my own personal “Nat-Geo” moments!  (Yes, Nat, pun intended!)

(Click image for larger view)

It is my hope that this project will reach, and even exceed, all its goals for the prothonotary warbler and its continued existence on this earth.  Further, it has been my privilege to be allowed to take part in this worthwhile project and to share it with you, my readers.

For the birds,

BW

 

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Comments

Prothonotary Warbler Project – Continued — 14 Comments

  1. Was looking for fig recipe and strayed to prothonotary warblers. Wonderful site. We had pw nesting in the shop for three years. Recently I saw one where driveway intersects a road in lower limbs of a pine tree.
    Do you have plans for building PW boxes?
    Beth

    • Hi Beth and welcome! So glad you hung around and hope you found a suitable fig recipe. I can ask Natalie if she can share those plans with my readers. If she has an e-version of the plans and gives permission, I’ll either post them at the end of the piece or email them directly to you! Thanks again!

    • Yes, they are beautiful, and aren’t their little faces just so cute?

      I can tell you one cause, because I talk about it on my tours. The short answer is wetland loss, but let me explain. Our migratory birds that come through the Miss. flyway, come from places far south of here, including places as far south as South America. When they leave those places to fly north for the spring and summer, they must cross the Gulf of Mexico. Well, there are no little “Birdie Rest Stops” in the Gulf (unless they land on a boat or an oil rig to rest, which has happened, by the way), so they are totally exhausted by the time they reach our shores. Well, as our coastline erodes, moving further inland, every year the birds have farther and farther to fly to reach land. This is called a “fall out”, when the tired, hungry, thirsty birds literally fall out of the sky to the ground. You can pick them up in your hand, they are so exhausted. Every year, fewer and fewer birds finish that journey alive, thereby reducing the numbers. I’m sure there are other scientific and biologic reasons, but wetland loss is the burr under my saddle, as you well know. So, for those birds that make it, the least we can do is provide them a ready-made home in which to grow new families! So glad you enjoyed the update, Cam!

  2. A great post, with delightful photos and good information. How long does it take to learn to handle birds that way without harming them? Are there courses taught, or is it an apprenticeship thing — or a combination of both (which is what I suspect). I’d be terrified of hurting the birds, although it clearly can be done without even any disturbance, let alone damage!

    • I’m not sure about her training, other than she is a biologist and is the bird conservationist at BTNEP. I don’t handle the birds, since I’m not in the least trained! She’s so gentle with them, and they just stay put while she assesses them. They don’t typically fret or struggle at all!

      • My mom raised parakeets when I was about 6 yr old. I remember how she would hold them as she put the bands on them. She was so gentle with them too and would spread and check their wings and feathers for pests. They had a large bird house in our back yard that was probably 12′ tall and about 10′ x 10′ square. The back was wooden the rest was a screen type wire. She had tree branches in it with nests and swings. Their feed bowls were nailed onto the back wall or frame parts in different areas along with water. I do remember old soda bottles upside down in trays in the cages. They were so pretty and all different colors. I think places like Woolsworth and feed stores bought them from her. She would save and bring 2 pairs into the house in the winter to restart her stock each year as the rest were sold during the summer.

  3. Their little faces are so cute! I didn’t realize their legs are thinner as they grow but it makes sense. Thanks for sharing knowledge, great pictures and your experience.

    • I was intrigued by that information, also. I asked about it, and as you say, it makes sense. Of course they wouldn’t apply a band that would restrict the leg as the chick grows, like putting a band around a tree trunk! That was my first thought!

    • Looks like we wrap it up next week with the “winterizing” of the boxes! It’s been fun, educational, sweaty, and tiring!

    • Yes, Choup. I watched both mom and dad bring a variety of little green worms (inch worms?), some kind of insect with green wings. If you enlarge those last three photos, you might be able to decipher what the parents have in their mouths!!! Whatever they’re catching, it only takes them a couple minutes to leave the box, catch something, and fly right back to feed the chicks!

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