Print this page


Posts categorized bluebird.

Mariton: Bluebirds Expecting

by Tim Burris, Preserve Manager

There are Bluebird eggs in two of Mariton’s nest boxes. Nesting activity started in one of the boxes on March 27 this year.  The two nests were started about a week apart.  One nest has 5 eggs; the newer nest has one egg so far.

There is also a moss nest started. It is probably a Chickadee nest, but I’ll have to wait to know for sure.


Mariton: More Spring Preparations

by Tim Burris, Preserve Manager

Nest box season is quickly approaching. I cleaned the boxes two weeks ago, and have been doing nest box maintenance.  Some boxes have been replaced completely, while others just received new roofs and some repairs.  Bluebirds have been checking the boxes for a few weeks now.  Now we just need longer days for the birds to get interested in nesting.

We also replaced the four bat boxes in the meadows this week. The bat boxes were originally installed as part of an Eagle Scout Project in July 2007.  Woodpeckers have bored some large holes in the boxes, and it was time to replace them.  Fortunately as part of his project, Austin built extra bat boxes for the future.  I have stored them all these years, moving them occasionally.  They are ten years old and dusty from sitting in the wood shop, but are otherwise brand new.

New bat box waiting for residents.

Mariton: Cleaning House

by Tim Burris, Preserve Manager

Photo by Carole Mebus

I cleaned out my nest boxes this morning. Eastern Bluebirds have been singing on nice days for a few weeks now.  I have seen Bluebirds occasionally over the last months.  During winter, they can feed on dry berries and other fruits to get them through the winter.  This was a tough winter though, because the drought last summer and fall didn’t leave much fruit for wildlife.  Fortunately it has been a mild winter so far, and the Eastern Redcedar (Juniperus virginiana) produced a good crop.

Mouse nest

This is a little earlier than I normally clean out my boxes, but it seemed like a good day to do the job. Bluebirds have started investigating the nest boxes looking for potential nest sites for future use.  As I expected, there were mouse nests in most of the boxes located in the thicker parts of the fields.  After cleaning out the old nests, I prop the box open with a twig.  It will help air things out, and deter mice from building another nest.  It is supposed to rain this weekend, which will also help in the spring cleaning.  I’ll monitor the boxes for the next two weeks and do some winter maintenance.  Then I’ll close them up just in time for Bluebirds to start house shopping.  I didn’t have mouse issues in the short grass areas of the fields, but I still propped open the boxes.

2016 NLT Nest Box Review

by Tim Burris, Mariton Preserve Manager

Photo by Carole Mebus

One of my roles, in addition to managing Mariton, is collecting information about nest boxes from the other NLT preserves. Some of the Preserve Managers are very involved in the nest boxes on their preserves.  Other managers utilize volunteers, including the Force of Nature, to manage their nest boxes.

Chickadee in a Mariton nest box by Carole Mebus

We often think of bluebirds when we talk about the nest box program. Bluebirds are important to Natural Lands Trust’s nest box program, but depending on the management goals of a particular preserve, other species also benefit.  For instance, Mariton’s fields are pretty small.  Early in the season it is good habitat for bluebirds, but later in the season it gets a little brushy for them.  Chickadees often do as well as bluebirds in our nest boxes.  Other preserves manage large swaths of grassland which provide a habitat that is quickly disappearing from Pennsylvania’s landscape.  This benefits many bird species, and while bluebirds use the boxes, this type of habitat is ideal for tree swallows.  NLT’s nest boxes provide nest sites for a variety of cavity nesting species, not just bluebirds.

Tree Swallows

In 2016, we had 15 preserves reporting nest box data. Again, a big thank you to volunteers who helped maintain boxes and monitor activity.  There were 298 boxes, and 252 of them showed nesting activity.

Bluebirds nested in 134 of the boxes and produced 407 fledglings.  (45% of boxes showed bluebird activity.)

Tree Swallows nested in 116 boxes (39%) and fledged 395 chicks.

House Wrens nested in 70 boxes and produced 125 fledglings.  Carolina Wrens also produced 6 young from the nest boxes.

Chickadees were in 14 boxes and produced 53 young.

Bluebird chicks

You may have added up the different nests above and realized that it exceeds the 298 nest boxes that were monitored. That is because 87 of our boxes were used more than once during the season.  House Wrens and Tree Swallows nest a little later in the season.  So, it is pretty common for them to use a box that may have been used by Bluebirds earlier.  Bluebirds often rear a second brood, generally using a different box, but sometimes reusing a box if it is cleaned out quickly.  This is a very good reason to remove old nests as soon as the young leave the box.

Mariton: Bluebird Progression

by Tim Burris, Preserve Manager.


Here are two different broods of Bluebirds hatched about one week apart. The photo above shows a brood that wasn’t hatched last week when I checked the boxes.  The Bluebirds in the photo below are less than two weeks old.  They grow fast.  The birds below will probably still be in the nest box next week when I monitor.  If they are still there, they will be leaving the box within a few days.


Nest Box Monitoring: Chickadees

by Tim Burris, Mariton Preserve Manager

Photo by Carole Mebus.

Photo by Carole Mebus.

We often call our nest boxes Bluebird boxes, but they attract a variety of cavity nesting species. It was the idea of putting up nest boxes that helped Eastern Bluebirds populations recover across the east.  I don’t have a problem with other species using the boxes.  I just put up more, so there is room for everyone.

I have been monitoring nest boxes for over 30 years, but it has only been about the last decade that Chickadees* have been using them regularly. There are lots of natural cavities in Mariton’s forest so I can’t explain the trend, but it mirrors the reports that I receive from the other NLT preserves.

Chickadee nest.

Chickadee nest.

Chickadees make nests of mostly moss with a layer of hair on top. I think the hair is used for insulation by the parents, so the female can spend more time foraging and less time on the nest.  If one is new to monitoring nest boxes, they may not realize that this plug or lid or hair can be easily lifted to count eggs and then replaced.  If you are afraid to check the eggs, the hair will disappear when the chicks hatch and you will be able to count the babies.

The same nest with the plug temporarily removed.

The same nest with the plug temporarily removed.

*(Mariton is a location where both Black-capped and Carolina Chickadees overlap. There is evidence that they are utilizing each other’s songs and hybridizing in this area.  It is almost impossible to tell the two species apart without a physical examination.  For that reason, most birders in our area now refer to them as just Chickadees, with no specification.)

Mariton: The First Eggs

by Tim Burris, Preserve Manager


I have been watching one Bluebird nest for two weeks in one of the boxes. This week, there are 5 eggs in that nest.  Another pair of Bluebirds have started nesting in another box.


Chickadees are building nests in three different boxes. None of the nests is completed, but the one above is getting close.  It won’t be long before I find eggs in one of these nests.

Mariton: House Cleaning

by Tim Burris, Preserve Manager

A mouse over-wintered in this nest box.

A mouse over-wintered in this nest box.

It is time to clean out your nest boxes.  A year ago, I wore snowshoes for my first check of the season.  The weather this year is very different, but there were still a lot of mouse nests that needed to be removed.  As I check boxes, I make notes of what needs repairing and replacement.  I prop the door of the box open with a stick to air out, and discourage mice from returning.  Next week when I make repairs, the sticks will be removed.

They're cute, but this box is for birds!

They’re cute, but this box is for birds!

Don’t procrastinate on your nest box maintenance. I think Bluebirds will be nesting early this year.  They will definitely be house shopping in the next few weeks, so it is important that you get things ready now.

They will be hear before you know it.  Photo by Carole Mebus.

They will be here before you know it. Photo by Carole Mebus.

Mariton: Bluebirds

by Tim Burris, Preserve Manager

June was very busy and I didn’t get a chance to post on the Blog.  Instead of my weekly updates on nest box activity, I am just going to show the progress of one particular box.  This nest box is located in the yard and I can watch it easily from the house.  This box was empty during monitoring on May 7, but I had watched bluebirds checking out the box.

May 13.  One egg.

May 13. One Bluebird egg.


May 21.  Five eggs.

May 21. Five eggs.


May 28.  Still five eggs.

May 28. Still five eggs. They must have hatched later that day.


June 9.  Four well developed young.

June 9. Four well developed young.


When I checked the box on June 17, the babies had fledged.

Mariton: Bluebird News

by Tim Burris, Preserve Manager

It has been so busy playing catch up this spring that Dan Barringer and I haven’t had time to post as much as we would like.   Suffice it to say that wildflowers are beautiful, and new ones are blooming each week at NLT’s preserves.  The neo-tropical bird migration has been awesome and I am looking forward to Mariton’s census on Saturday.


Five Bluebird Eggs

Five Bluebird Eggs

And yes, there is nesting activity in the nest boxes at Mariton.  This Bluebird nest has 5 eggs.  Tree Swallows have moved into two other boxes, and I think a Tufted Titmouse is nesting.  (Time will tell, Chickadee nests look very similar).


  • expand2017 (41)
  • expand2016 (141)
  • expand2015 (167)
  • expand2014 (197)
  • expand2013 (192)
  • expand2012 (241)
  • expand2011 (244)
  • expand2010 (223)
  • expand2009 (233)
  • expand2008 (201)
  • expand2007 (227)
  • expand2006 (269)
  • expand2005 (187)
  • expand2004 (5)