AT THE MARTIN TOWERS

Purple Martin tower at Mud Lake Park

I had an opportunity this morning to watch the counting of eggs and nestlings of the Purple Martins down at Mud Lake by the Mississippi River. Together with some staff from the County Conservation and their kids we were invited to see how the nest gourds are maintained and kept clean during and after the time of incubation.

Ry, on the right, had lowered the gourd rack to the ground and then opened each one briefly. The kids helped counting and put the results in a tracking list for later evaluation. I was allowed to point the camera into the opening of one of the gourds so I can show you now how it looks inside with most of the martins already hatched.

Some of the chambers required a little more maintenance. When the nesting material was infested with bugs and possibly parasites, Ry carefully placed the young Purple Martins in a bucket for a short time, emptied the gourd, and replaced the old infested nesting material with new wood chips, or sometimes uses pine needles. This all happens calmly and relatively quick, so the gourd rack can be cranked up and the parents are able to feed the hungry bunch in the nests again.

It was an exciting experience, including some good conversation with everybody who was there. Thank you to Ry for a good explanation of the process and to Mike for inviting me!

Purple Martins at Finley’s Landing, 07/15/2025

TENDING A SECOND BROOD

Male Eastern Bluebird

It’s exciting to report that our pair of Eastern Bluebirds at the edge of the woods behind the house is working on a second brood. The first one in June contained 4 eggs and I saw three of the juveniles in the backyard on June 28th. I read in the book ”Bluebirds!” by Steve Grooms & Dick Peterson that about 65% of the eggs hatch. With other words, counting three fledgelings after they left the nest seems too be a success.

Shortly after the first brood I had cleaned out the nest box but a few days later one of the male House Wrens had filled it with small twigs and sticks to claim it for himself. I cleaned out again and and a couple days later the female bluebird had built another nest from grass and other soft material. About a week ago I checked the nest again and four eggs were laid. This morning another check revealed that five eggs are in the nest box and none had hatched yet. Looking inside takes only a few seconds and I only do it when both parents are not present.

Female Eastern Bluebird

This was a good reason this afternoon to sit in a camping chair away from the box and watch the bluebirds tending their nest. It was quite warm again today and the female retuned to the nest every 15-20 minutes and spent about 1-2 minutes in the nest box. The male bluebird guards the place from nearby trees and sometimes comes to the roof of the box. The incubation of the second brood takes about 13 days and I’m sure we are not far away from having the babies cracking the egg shells.

Nikon Z6 III, Nikon NIKKOR Z 600 f/6.3 VR S, Nikon Z Teleconverter TC-1.4x Induro GIT 404XL tripod, Induro GHB2 gimbal head, Westscott FJ80 II speed light,   @ 840mm (1260 mm equivalent in DX mode), 1/125s, f/9, ISO1600

It was a great opportunity to work with the ”Small Bird Rig” again (see my blog post from June 8th for details on this new setup). The Westcott FJ80II speed light was set to manual mode (range 5) and this very subtle hint of flash reveals the colors beautifully in this ambient light situation with the sun muted by the canopy of the trees.

I have been asked by a photography friend a little while ago about the sharpness of the Z 600 f/6.3 lens combined with the Z 1.4 teleconverter. Well, here is a photo I created today with this combo and also shot in DX mode, means with a smaller part of the sensor. This makes it an equivalent with a focal length of 1260 mm. The photo was shot at 1/125s from a tripod and is not cropped. The low resolution image here in the blog may not reveal every detail but comparing the original RAW files with each other I can’t see any decrease in sharpness by using the teleconverter. This was not always the case with older equipment I used to own.

BUSY PURPLE MARTINS

Male Purple Martin, Mississippi River, Mud Lake, Iowa

I still have a few photos from our recent trip to Minnesota but today I like to share some actual pictures that were made yesterday. I had received an information about the current breeding activities of the Purple Martins (Thank you Mike!) and went down to Mud Lake at the Mississippi River. Three days ago both breeding towers had more than 75 eggs and almost 30 nestlings had hatched already. The parents were very busy to feed and to guard each nesting chamber. I believe each tower holds 18 chambers.

Female with her latest catch at the martin house

I have plenty of pictures with martins sitting at the entrance of a nest box but I really wanted some shots with a bird in flight, approaching the nest or just hovering in front of it.

However, the second image shows a female with a dragon fly in its bill and waiting in front of the entrance hole of her nest. It took about four minutes before she turned around and entered the box to feed the offspring.

Female Purple Martin

If you are not familiar with the habits and biology of our largest swallow, you can find a lot of information about these birds on the websites of the CornellLab or the Purple Martin Conservation Association.

https://www.allaboutbirds.org/guide/Purple_Martin/

https://www.purplemartin.org

The Purple Martin is a very interesting bird and it is fun to watch how they catch all their food in flight and get their drinks by scooping water from the surface of the river or pond with their lower bill.

MANY NESTING ACTIVITIES

Eastern Bluebird. The male observes the neighborhood in a nearby tree before he brings food to the nestlings.

There is a lot going on in the woods and the nest boxes around here. Hard to follow it all with equal attention.

The Eastern Bluebirds in the nest box have hatched a few days ago. I had a brief look into the box but wasn’t able to see how many nestlings came out of the five eggs because the nest is very deep. Time will tell. Both parents are feeding vigorously and bring caterpillars, spiders, little worms, and moths to their offspring every few minutes. I saw the male still catching insects tonight at 8:45PM . It’s a hungry bunch!

Female American Robin preparing a new nest

Yesterday a female American Robin was building a new nest in a tree just across from my office window. It might be even on top of a first nest that most likely was built at the end of April already. With other words, they work on the second brood already. The female collected very quickly dried grass and other plant material and glued it together with wet dirt from underneath a bird bath. After dropping the grass in the nest the robin rigged it with her feet and it looked like she was trampling it in place. The male watched the surrounding area and chased everyone away that came close to the nest. I saw him a couple times going after the bluebird.

Male House Wren inspecting a nest box.

The tiny male House Wren still sings his heart out to attract a female to one of the nest boxes we provide for them since many years. Once in a while he inspects one of the nesting chambers and the photo was made when he came out of the hole. As I said before, hard to follow all nesting activities at this time of the year…

All images: Nikon Z6 III, Nikon NIKKOR Z 600 f/6.3 VR S, Nikon Z Teleconverter TC-1.4x, Induro GIT 404XL tripod, Induro GHB2 gimbal head,   @ 840mm,

NATURE CLICKS #606 - BOBOLINKS, READY FOR THE NESTING SEASON

Male Bobolink, Technology Park, Dubuque, Iowa

Bobolinks have one of the longest migration routes. They spend the winter in Bolivia, Paraguay, western Brazil, or northern Argentina. They breed in grassland habitats and it is important that the grass is not mowed during the breeding time. This happened unfortunately here in the Dubuque, Iowa area in one of the habitats in 2023, due to human ignorance. The Bobolink is one of the few songbirds that undergo two complete molts each year. After breeding the male changes to a more drab and camouflaged plumage.

I found at least 4 male Bobolinks today and saw briefly even a female in the grass of the Dubuque Technology Park. The Dubuque Audubon Society has worked with the city so that mowing in the undeveloped lots takes place only outside of the nesting season. Signs around these areas inform the public about this natural treasure. Other bird species can be present as well and toady I saw American Robins, an Eastern Meadowlark, Barn Swallows, Red-winged Blackbirds, and an Eastern Kingbird.

I made a number of shots while standing or kneeling at the edge of the grassland lots but the distance to the birds was a little bit too far for a pleasing photo. Later I parked the car with the driver side against the curb and shot both photos from my ”mobile blind”.