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Delaware National Estuarine Research Reserve

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  Archived Posts From: 2018


DNERR’s Tree Swallows and Bluebirds Need YOU

Written on: July 11th, 2018 in Blackbird Creek ReserveEducation & OutreachSt. Jones ReserveVolunteers

DNERR’s Tree Swallows and Bluebirds Need YOU

Spring is here, and the St. Jones and Blackbird Creek Reserves have sprouted a number of mysterious, wooden boxes affixed to PVC poles. Where did these boxes come from? And why?

At the Blackbird Creek Reserve, a nest box is clearly marked as being monitored by DNERR. Photo: M.L. Christmas

With such questions in mind, this writer approached Christina Whiteman, DNERR’s Environmental Scientist and Stewardship Coordinator, and Kari St. Laurent, DNERR’s Research Coordinator. Here is what they said; and you, the readers of this blog, can volunteer to be in on the fun!

What is the purpose of the nest boxes? Are they for Wood Ducks? Or Bluebirds? Or just what? Christina responded, “They are for the use of cavity‑nesting birds, such as Eastern Bluebirds and/or Tree Swallows, for breeding and brooding purposes.”

Why the PVC posts? Aren’t they typically wood? “That is a strategy being tried for avoiding the incursion of predators, like snakes. Snakes cannot easily climb PVC, unlike when the traditional, wooden posts are used.” (One can certainly imagine why a snake and a nest box full of eggs or chicks is not a good mix.)

It’s “problem solved,” then, with PVC! “Not exactly. One ongoing problem we have is House Sparrows, a species that often takes over nest-box spaces and crowds out the other species. We are still trying to devise strategies for deterring them.”

 So, people are an important part of the equation? “Yes! Some human involvement is needed: for monitoring the nest boxes and documenting the avian activities.”

A line of nest boxes at the ready at Blackbird Creek Reserve, just a portion of those on the premises. Photo: M.L. Christmas

This writer did not need to inquire where this help was needed. She had been at the Blackbird Creek Reserve earlier in the week and had noticed a number of nest boxes throughout the complex, including a sweeping array in the Reserve’s “back 40”; and on the way to this interview, she also saw a line of nest boxes at the St. Jones Reserve.

So, what specific type of help is needed, and how is it accomplished? Christina showed this writer an amped-up, angle-y, oversized, dental-mirror-like thingy that is used for peering into the nest boxes without disrupting the inhabitants. Any Philadelphia-area folks familiar with Elfreth’s Alley would liken the implement to a “Busybody Mirror,” a Colonial-era device attributed to Benjamin Franklin. That specialized type of mirror, still being sold today, allows a homeowner on the second floor of a home to discreetly view who is calling at the front door. This is similar, but in reverse: allowing the nest-box checker, when standing at the “front door” of the nest box, to peer inside without disturbing the avian occupants.

Can anyone participate? “Yes, and the nest boxes are also an ongoing research-intern project. The training in the proper protocol is provided via the Cornell Lab of Ornithology’s NestWatch program. The database tracks the location of a nest box and which species is using it. We have been monitoring our boxes at DNERR for two years. Our interns and volunteers can become certified in nest-box monitoring, and they help monitor the boxes throughout the summer. We also have a partnership with Delaware State University [for monitoring the boxes at the DNERR], and Del State bands the Eastern Bluebirds that are in our boxes.”

How has that been going? Any discoveries? “They have been banding some of the birds to see who comes back or to determine if they are overwintering.

A peek inside a nest box to check on its precious occupants: Babies on board! Photo: Molly Williams, EPSCoP research intern from 2016.

We start checking the nest boxes, and scouting the arriving birds for color‑coded bands, in April. That was when, the other year, we learned of a female Bluebird, at the Blackbird Creek Reserve, laying white eggs. They were lacking the normal light-blue pigmentation. A small percentage of Bluebirds have white eggs, and the interns from Del State banded the chicks that hatched from those particular eggs, for the purposes of future monitoring.”

What else is needed, apart from human assistance — or should that be “assistants”? “We would like to get more Bluebirds at the St. Jones Reserve, though we might not have quite the right environment for them here, as we do at Blackbird Creek. Here at the St. Jones Reserve, the conditions are good for Purple Martins. We have found that the houses with the crescent-shaped openings work best here. We had been trying to attract Purple Martins, with mixed results in the past, but were not fully successful until last year.”

Bottom line for the readers of our blog? “We would like to get some volunteers involved with the monitoring process and with helping clean out DNERR’s nest boxes in the fall. The Cornell Lab of Ornithology’s NestWatch website contains a lot of helpful information,” Christina said.

Kari St. Laurent remarked, “One of the things I like best about the Cornell Lab’s nest-box program is that participants can be certified in monitoring and then take home the ‘recipe’ [for maintaining nest boxes in their own yards]. It is something that people of all ages can do. I know of a research paper from about two years ago that used NestWatch data about Tree Swallows. That is an example of how citizen-science projects, such as these, can be useful for others’ research.”

Christina then noted that anyone “can see the real-time data at the Cornell Lab of Ornithology’s NestWatch site: <https://nestwatch.org/>.”

Baby birds: What’s not to love? Photo: Kathleen Carey, conservation intern from 2016.

Kari continued, “Nest-box monitoring is ‘warm and fuzzy’ — but is also very important. As mentioned, we can fold this data into other research projects. We even studied the effect of emptying most of the boxes but leaving a few old nests in others. Would the birds have a preference, when selecting a box for the new season, between an empty box or using one containing a nest left over from a previous brood? Would the existence of the old nests help or not? It turned out the preference was really for where a box was located — adjoining the meadow at Blackbird Creek, as opposed to being closer to the woods — and not whether a nest was already in place inside a particular box. Of course, we always need more data before we make conclusions.”

This guest-blogger could not help but mentally make the correlation that, just like the real-estate-agent adage, even for Bluebirds the key to a property’s success is “location, location, location”!

And to further anthropomorphize: Who can look at these baby-bird photos provided by past DNERR interns and not think “Cootchie-cootchie-coo”? Adorable, yes, but the nestlings are also an important part of our ecosystem. Who knew citizen science could be so cute?

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Text by M.L. Christmas; photo credits as noted.

M.L. Christmas, MSM, is a freelance writer/editor living in the Dover area. She is a longtime member of Delaware Press Association and the National Federation of Press Women.