Tag Archives: babies

Getting airborne when lift is lacking….

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If you’ve had the good fortune to watch a bird caring for nestlings and then encouraging them to enter the big wide world, you might think that the young ones automatically know how to fly. But my recent observations of a ruby-throated hummingbird family (Archilochus colubris) showed me that a learning curve — albeit not a long one — may be involved.

On the 29th of April, my friend Ace and I had the good fortune to spot a female hummingbird. We discovered that she was gathering construction materials for a nest with inside walls that included plant down.

 

 

 

 

 

 

She was camouflaging the outside of the walls with lichen.

 

 

 

 

 

 

As she worked on the nest, she sat in it periodically, moving her body to form the cup shape and tamp down the bottom.

 

 

 

 

 

The walls expand as the eggs hatch and nestlings grow; this is possible because the walls are held together by spider web and caterpillar webbing (6 May).

If we hadn’t seen her working on the nest, we likely would not have seen it. It was very cleverly placed near the crook of a small branch that had lichen growing nearby (13 May).

I noticed a twig curving down from the branch beneath the nest and that became the marker for finding it again — not always an easy task as the hummer home blended in so very well with the tree she had chosen.

Just after mid-May, I had to stop my observations as I had the immensely good fortune to visit Yellowstone National Park (blogs on that coming up!). It was only on 4 June that I was able to visit the hummer nest again and it was a thrill to see two babies had emerged from the coffee bean-sized eggs.

During their first days, young hummingbirds are very vulnerable. They are blind for about 9 days and only begin to grow pin-like feathers after about 10 days!

Mom would come by and regurgitate food (insects and nectar) into their open mouths.

 

 

 

 

 

When the chicks grew enough to peer over the nest’s edge, we were able to watch them surveying their surroundings.

The two of them would look around in unison.

They moved around the nest more and more, jostling for space. By 3 weeks of age, ruby-throated hummingbirds are fully feathered and getting ready to fledge.

 

 

 

 

 

 

On 7 June, I had a premonition that fledging was going to occur that day. I had volunteer duty in the morning (to pull invasive plants at a local reserve) so I could only visit the nest briefly before going to work.

The babies were both flexing their wings a lot. Hummers typically flap their wings 50-200 times per second! It turned out that they needed to exercise a lot, or they weren’t going to be able to get the lift needed to leave the nest.

The nestlings flapped back and forth as they revved up their muscles for a coming take-off. Their pectoral muscles need to be strong for their airborne flights and may account for up to 30% of their body weight.

Watching with excitement as I maneuvered a bit to get better lighting for photos, I saw one of the little ones begin to lift (above). S/he flapped furiously. I got a photo of the lift off but not the actual departure from the nest.

One nestling remained and s/he began flapping vigorously.

I had to stop my vigil as it was time to get to the nature reserve. While leaving, I ran into Ace and told him that one hummer had just fledged, and the other was getting ready so that he could see the event!

After my 2-hour shift, I drove back to the nest. Ace had let me know that Chick No. 2 had not yet left while he was watching. Sure enough, when I returned the little one was still there (above).

He moved around a lot but didn’t seem to be going anywhere.

 

 

 

 

 

It seemed that Chick No. 2 was not getting the lift needed to soar up and away despite all its efforts.

Mom came to give some encouragement.

She also gave Chick No. 2 a bit of nourishment.

That seemed to provide the young one with renewed energy as the practice wing flapping resumed vigorously.

After a couple hours, I needed to leave to do other things. I took a few more photos of the hard-working almost-fledgling.

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The next morning, I visited the hummer home again wondering whether anyone would still be in residence. The nest was empty so Chick No. 2 had departed the previous afternoon or evening. But as I watched, a hummer was zipping around the tree and the nest.

I think it was Mom. She may have been considering whether the nest could serve as a spot to raise another brood. It might also have been one of the young ones returning for a last look at home.

Observing the hummingbird nest over a period of weeks was a wonderful learning experience. I’ll treasure the memory for a long time to come. And I now have an even greater appreciation for these tiny birds that become flying gems in our natural surroundings.

Avian generations in the making – part 3A: raising and feeding babies

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So here in North America, it’s approaching winter and it may seem a bit weird to have another blog at this time on birds raising their young. But I wanted to complete the series even though it has been delayed because of my volunteer activities and commitments the past month. Also, it is now late spring in the Southern hemisphere so for some people this is seasonal and there are other birds around them that are getting ready for babies, though different species than these American robins (Turdus migratorius). Because this part kept growing longer as I worked on it, I’ve divided it into two parts – this one on raising the babies until fledging and the next one on fledging and post-fledgling care. I hope all of you who read this will enjoy it no matter where you live.

It’s fascinating to me to watch the birds during their reproductive cycle; I always learn something new. Once parent birds have completed a nest to their liking, the female lays her eggs and proceeds to brood them, with some species sitting on the eggs almost full time right away and others taking breaks.

           

Carolina wren (Thryothorus ludovicianus)              Eastern bluebird (Sialia sialis)

An acquaintance recently told me about a friend of hers who commented that she had seen a very pregnant goose that was so fat, she was waddling. The acquaintance proceeded to give an avian reproduction lesson to her friend – a woman in her 80s – who apparently did not know all birds lay eggs! Even after babies hatch, the Canada goose (Branta canadensis) may still look well-fed!

Some bird species have young who are “precocial”, that is, they are covered with downy feathers and have open eyes when they hatch and are soon able to feed themselves. These species include turkeys and ducks, like these mallards (Anas platyrhynchos), and the young often leave the nest soon after birth (which makes them “nidifugous” – good Scrabble word!). The newborns may look fuzzy but it’s not long before they start to take after their parents’ looks.

Other birds, such as songbirds, are altricial (as are human beings) – they are naked and helpless at birth and require considerable care before they can walk, fly and feed themselves. If you have some in a nest that is easily observable (and you can take photos when parents are not there so you don’t distress them), it’s interesting to see how the babies develop.

               

Carolina chickadees (Poecile carolinensis) on 18 and 22 April           

Brown-headed nuthatches (Sitta pusilla) on 13, 25 and 29 April

 

 

Eastern bluebirds (below)

     

As the mother incubates the eggs, her mate will often feed her so she doesn’t have to leave the nest. This young osprey (Pandion haliaetus) was assiduous in bringing his female life companion fish. Then as the babies hatch, in many species both the male and female parents get busy bringing the young frequent meals.  It’s estimated that Carolina chickadees, for example, will bring over 5000 insects to their brood before fledging!

Northern mockingbird (Mimus polyglottos)

     

House finch (Haemorhous mexicanus)  and Red-headed woodpecker                (Melanerpes erythrocephalus)

              

Orchard oriole (Icterus spurius)                  Blue grosbeak (Passerina caerulea) 

  

Eastern phoebe (Sayornis phoebe)

In some species, the previous year’s young will help their parents with the new brood. Brown-headed nuthatches and American crows are examples of this. A pair of Canada geese that I observed this past spring seemed to have a domestic goose helping them out.

The parents have other chores, too. They must keep the babies safe from predators – Both American crows (Corvus brachyrhynchos) and common grackles (Quiscalus quiscula) will be chased away by songbirds, for example, because these birds will raid nests to eat eggs and babies. But the grackles must also protect their own young against the crows, pursuing them non-stop to drive them away.

 

For other birds, protecting the young can be more difficult. This mother wood duck (Aix sponsa) was raising her brood in a pond that was home to at least three large snapping turtles (Chelydra serpentina). Ultimately, another birder and I thought she only had two ducklings survive.   

Keeping the nest reasonably clean is another chore. The babies make this task a little easier than you might think because they defecate into a mucous membrane that forms a sac. When you watch a nest box, especially when it gets closer to fledging time, you can periodically see the parents flying out of the box with a white blob in their mouth, which turns out to be a fecal sac. They either discard it elsewhere or sometimes eat it for some nutritional benefit.

        

Brown-headed nuthatches

This year, I was surprised to have caught a female blue grosbeak during the cleaning – it appeared that she was actually pulling the fecal sac from the baby! Later, I read that some species stimulate defecation by prodding the babies’ cloaca so they can get on with the chore. I also caught a photo in which a baby bluebird had just presented its rear end to the parent for removal of a sac. I could imagine that some human parents might think a fecal sac would be a cool avian adaptation for their babies to have – no more dirty diapers and expense for diapers either! (An idea for an SF short story?)

     

 

After all their efforts, the parents are usually ready for those babies to fledge – the subject of the upcoming last blog in the series.

 

 

* Not all the photos in this blog are of great quality, I know, but my intention was first to show behaviors and secondarily to have some nice shots in the blog.