These photos of Eastern Bluebird nestlings were taken in a nestbox in my backyard in July The young became so accustomed to monitoring that they did not get agitated. I continued to actively monitor after Day 13 out of concern for a runt in the nest.
I did not handle the nestlings. These photos might help you figure out the age of your nestlings. There is also a great FREE children's activity book on Mountain Bluebirds - pages have photos of each day of development. The male bluebird scouts out nest site locations in February and March. It is the male that sings. Photo by Wendell Long. Nest building usually takes days. During colder weather, it can take longer. A Gilbertson box was chosen this year for both the first and second broods.
I don't usually get bluebirds in this style box, but it is good for photography as it opens from the top. This box sports a sparrow spooker that was installed after the 1st egg had been laid to prevent House Sparrow attacks. Bluebirds only lay 1 egg per day. This particular nest is made of pine needles.
Three eggs laid so far. Bluebirds usually lay - sometimes 6 or 7. Second and third broods tend to have fewer eggs. This is a second brood for this pair. Incubation does not begin until all eggs have been laid, so they will hatch at the same time. Since it was hot, I rarely saw this female on the nest. Incubation typically lasts days. The female may wait about a week to start incubating the clutch if weather is still cold.
Keith Kridler notes that bluebird eggs are rather dull when first laid, but get slick and shiny when they are close to hatching about 10 days after being sat on, turned regularly by the mother, and rubbing against each other. The embryos use their "egg tooth" to peck their way through the shell. This hard tip on the beak eventually falls off. Eastern Bluebirds take hours to pip through the shell it can take an Albatross 6 days!
It can take rarely 72 hours for all eggs to hatch. NEVER remove unhatched eggs until 4 days have passed since the first one hatched. Note: some people count this as Day 1. See another close up of a newborn. Notice the wet gray down on the recently hatched nestling. Three down, two to go. The hatchlings have bright coral-pink skin. Eyes are sealed shut. The abdomen of the bird at the top of the photo is swollen because prior to hatching, the chick Baby Blue Eyes - Marty Colburn - Hard Timing most of the liquid in the egg, and pulls the membrane yolk into its abdomen.
They look like hairy shrimp at this stage, with sparse, wispy tufts of down on their heads and backs. The female will brood them to keep them warm. One egg left. Hatching often occurs in early morning, Despite floppy necks, gaping is automatic. The nestlings have powerful "hatching muscles" on the back of their head and necks that probably help. At this stage, babies are quite fragile and should not be handled.
If you want a count, whistle and they should gape. At the end of Day 0, one egg has still not hatched. The babies heads look huge. Their wings are nubs, and their legs are weak and spindly. Their eyes are closed. By Day 1, all eggs have hatched. Parents both male and female feed the nestlings at least twice an hour. Since their digestive tracts are not developed yet, they do not fully digest food, so parents Baby Blue Eyes - Marty Colburn - Hard Timing eat the droppings.
Later they will remove the fecal sacs 60 to 70 bundles a day! If any eggs haven't Baby Blue Eyes - Marty Colburn - Hard Timing by the 4th-6th day after the others, it's okay to remove them. Unhatched eggs can explode into a stinky mess and cause other problems. Nestlings can't regulate their body temperature for the first six days. Cheeping is louder. Eyes may begin to open as slits. Eyes usually open on Day First feathers burst from tip of sheaths.
The female no longer broods, because the young can maintain their body temperature by Day Eyes open on Dayand feathers continue to come out of sheaths. By now they should weigh a little less than an ounce grams. Feeding visits are about every 5 minutes. Nestlings may cease gaping when nest is monitored. Instead they hunker down, eyes closed. The runt still gapes. I am concerned about the smallest baby.
She seems far behind the others developmentally - notice the difference in feather cover. By this age, nestlings may show fear if handled, and can crawl. The runt continues to gape. The hungriest baby cheeps the loudest and gapes the most to stimulate feeding by the parents. Feather sheaths start to disintegrate leaving a white dust behind and wing feathers begin to emerge. Nestcams indicate nestlings start to stand up at this age.
By Day 11 the nestlings start to preen, pulling at the sheaths of emerging feathers. They may stretch and hop a little to strengthen muscles. I did a nest change on day 12 as I saw blow fly larvaeand was concerned about them.
I wouldn't recommend it after this date as babies might prematurely fledge. By Daymales have bright blue feathers. There are usually more females than males in a brood. Stop active monitoring now to avoid premature fledging, unless you suspect a problem. You can still check the box from a distance to verify that the parents are feeding the young. One way to tell they are at this age is that the parents tend to only dip their heads into the box to feed Loose In Space - Jahtari Riddim Force / Disrupt - Loose In Space / The Stars My Destination may still enter to remove fecal sacs.
Females have white edging on outer tail feathers. This nest holds 4 females and one male. By Piano Sonata No.
18 In G Major, Op. 78 / D.894, Fantasia (1826) - 3rd Movt. Minuetto & Trio - Schu stage, babies are strong enough Baby Blue Eyes - Marty Colburn - Hard Timing cling to the entrance of the nestbox to look out.
They have a narrow ring of white feathers around each eye, and their breasts are speckled with gray. Notice the cobalt blue feathers of the male. Nestlings exercise more, and may stand on the edge of the nest and look Baby Blue Eyes - Marty Colburn - Hard Timing of the nest cavity. When I took these photos since they were after Day 13 I blocked the entrance hole and moved quickly and quietly.
Premature fledging is less Tout Semble Si. - Zebda - Essence Ordinaire + Le Bruit Et LOdeur in a top opening box.
Bluebirds generally fledge days after hatching, typically Development depends on food availability. The parents often get more defensive around the box at this time, and may divebomb passersby.
Nestlings are able to hop. Western and Mountain Bluebird s typically stay in the nest longer than Eastern Bluebirds - days, depending on the weather. All 5 babies are still in the nest, eyes open, fully feathered. The runt is on the bottom of the pig pile. By early morning, four have fledged. At fledging, the babies weigh slightly more than their parents.
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