Displaying items by tag: Nesting

These nest box instructions were first used in an early Flight, and have proved very effective since then. So for the handy men and women among our members here is a new occupation for you over the summer months.

The Wairarapa breeding programme is going very well at Pukaha Mt Bruce. The Shore Plover programme has hatched 22 healthy chicks so far this year with five pairs now sitting on their third clutch.

The two pair of pateke are nesting again having so far successfully reared 12 ducklings between them. 

The whio pair has three ducklings and there are three juvenile kiwi in the creche nearly ready for release as well as a kiwi chick hatched on Christmas Eve and one kiwi egg externally pipped and will hatch any day.

One red-crowned kakariki pair have three chicks to look after while another pair are waiting for their five eggs to hatch. 

Wild kaka have this year utilised three of the nesting boxes with one pair already fledged and another three chicks not far behind.

Urban bittern chicks get into strife

Now, if I was to ask how many of you have seen a juvenile bittern or a bittern nest, I think it’d be safe to assume that most of you haven’t. And that’s saying a lot given that you are all wetland enthusiasts who regularly work and play in these kind of habitats.

So when we got a report that a female bittern chick had been found wandering along a road in Christchurch you can imagine our surprise. What was one of the most cryptic and secretive  wetland birds doing on a road in the city? And the surprises didn’t end there – a few weeks later a second female bittern chick walked into a residential garage, only 500m from the location where the first bittern was found. 

There had to be a nest nearby – but where?

Both bitterns were very skinny and clearly  dehydrated. They were taken to bird rehabilitator Jackie Stevenson, who set about trying to fatten them up and get them feeding for themselves. In the meantime, local  ornithologist Peter Langlands set about trying  to find their nest.

Now this is no easy task. Bittern nests are  tricky to find. A broody female bittern will build her nest by bending blades of raupo to form a floating platform that is perfectly  hidden in the thick vegetation. And she’s not necessarily alone. Male bitterns can have  multiple females, which all appear to nest within close proximity to each other.

Once a mother-to-be is happy with her nest she’ll lay between 3 and 5 eggs before starting to incubate. She hatches the eggs and rears the chicks alone, apparently chasing the male away if he tries to get too close. While incubating, she’s almost impossible to see as her streaked plumage blends perfectly in  with the surrounding vegetation. Occasionally she’ll slip silently off the nest to feed, but only momentarily as this leaves her eggs vulnerable to predators. 

After about 25 days, her eggs will hatch to produce little fluffy chicks with Albert Einstein inspired hairdo’s. These fuzz balls, emerge as masters of disguise straight from the eggs, and will adopt a perfect ‘freeze pose’ that looks similar to that of the adults if they are disturbed. Chicks fledge at about seven weeks old. However, there is some suggestion that they may start wandering from the nest as early as two weeks old - which is perhaps how one chick ended up on a city road and the other in a household garage.

Midway between the locations where these two birds were found lies Travis wetland, a 120 hectare swamp complex that has been  restored over the last 15 years by the Travis wetland trust and the Christchurch council.  It is the most likely place where these two birds came from. As it happens Travis is a noteworthy place, with an interesting history. In the 1960’s, this beautiful wetland was under threat from developers, who wanted to convert it to a residential area. Luckily, the locals had other ideas. They realised the importance of the site’s natural biodiversity, and argued long and hard for its protection. After a long battle that involved a petition signed by almost 7000  people, biodiversity won out, and in 1997 the site became a natural heritage park. 

And lucky for bitterns that it did!

Since then, these two bitterns have done well in  captivity and we were able to release them over the festive season - one along the Waimakariri river and the other at Harts Creeks. We attached radio transmitters to both bitterns, one of which was kindly funded by Ducks Unlimited. Both of these birds will be tracked regularly by local enthusiasts and, as female  survival and breeding success is the secret to  saving a species in decline, and these birds are the only females to carry transmitters at the moment - the information we gain will be essential for saving the species. 

Emma Williams

And thanks to Gill Lundie for organising the school visit. 

The photo is of spoonbill chicks in a nest early this year. The nest itself is a pretty loose affair of sticks placed in the base of a dead willow tree and surrounded by open water on all sides. As the chicks age the nest becomes a lot whiter, the result of droppings from both the chicks and their parents.

This was the first record of spoonbills nesting at Boggy Pond and only the second for Wairarapa.

They have been seen more often in the wider area over the past few years with the increased area of shallow wetland created by DU’s Wairio restoration project likely to be providing a good reliable food source.

I think, also, that the predator control in the area has been a big part of supporting these nests once they start and giving the youngsters a decent chance of fledging.

We hope that this is the first of many!

Earlier in the year a team took the canoe to  chase and spray purple loosestrife.

On the way out we noted a big flock of  spoonbills at the northern end of the lagoon and on the way back we came across some nests in the bases of sprayed willows. 

We didn’t approach too closely, but through the telephoto it looked like two chicks at least in each.

It was quite a shock to come across these, a  pleasant one too, as you’d imagine. This is the  second confirmed nesting site at Wairarapa Moana.

We plan to follow up the loosestrife work and will check on these chicks and have a look over a wider area to see if there are more.

I think this is a result of the combination  of willow spraying opening up the lagoon  and creating the right conditions for nest  building and the pest control keeping the nests alive instead of providing food for hungry mammals.

Tony Silbery

Kaiarahi- Koiora Rereketanga (Ranger,  biodiversity) DoC. 

Each spring, Canadians herald the sights and sounds of waterfowl as they flock to their nesting grounds. But after their long trips, life for our feathered friends isn’t easy. Ducks – especially females – undergo arduous physical and biological processes before, during and after their journeys. And once here, most hens have one shot to raise a brood.

It’s early June on the Saskatchewan prairies. A slight breeze gives her wings a lift as she circles over a patch of native grassland next to a shallow pond. She decides to land in a small clearing, then walks into the grassy cover. It’s the third spot she’s scouted. She feels safe here.

In the coming days, this blue-winged teal hen will construct a nest with nearby vegetation and line it with down plucked from her breast. She’ll feed on invertebrates to build her energy for an important role: producing a brood.

It’s no easy gig. She’ll need all the energy she has to give.

When male and female waterfowl prepare for their journey from their southern wintering grounds northwards to Canada, they do so in similar ways. The process differs between the sexes once they arrive. David Howerter, PhD, director of national conservation operations at Ducks Unlimited Canada (DUC) explains how, and why ducks do what they do – before and when they get here.

A shared experience: preparing for migration

Feeling restless – Ever wonder what pushes migratory waterfowl to bid adieu to their warm winter homes?

It’s a physiological process called zugunruhe (pronounced: zoo-gun-roo). This German term refers to the restlessness birds experience as migration nears. Zugunruhe is triggered by the endocrine system (a collection of glands that release hormones into their blood stream) in response to longer daylight hours. “As it gets closer to the time for these birds to migrate they become increasingly active,” says Howerter. “They’ll spend more time flying and their movements will begin to orient in the direction they intend to migrate.”

No exceptions – Zugunruhe impacts migratory waterfowl wintering close to the equator, where daylight hours remain consistent, year-round. This may be a result of evolutionary hangover from when the species had a different distribution, or because of the changing angle of the sun.

Packing on the pounds – “Before ducks begin their journey north, they’ll go through a phase biologists refer to as hyperphagia, where they’ll spend a lot of their days consuming calories,” explains Howerter. “This is done to prepare for their long trip.” Like zugunruhe, hyperphagia’s also triggered by hormonal changes, influenced by changing daylight hours.

Growing closer – Migratory waterfowl can only procreate from spring until late summer. This is because in the “off-season” their reproductive organs shrink, making it easier to fly over long distances. As birds close in on their breeding grounds, their endocrine system releases hormones that stimulate their reproductive organs to grow larger again in anticipation of breeding.

It’s all about her: producing a clutch

Once waterfowl arrive at nesting sites, the male-female experience begins to diverge. “Once they have fertilised the eggs and the hen is incubating, the drakes will take off. Often they’ll go further north, to the boreal forest,” says Howerter.

Meanwhile, the hens prepare for one of the most difficult processes they’ll go through in their lifetime: producing a clutch of eggs.

Size matters – How waterfowl behave once they arrive at the nesting site depends on whether they’re capital or income breeders. “Capital” breeders are large-bodied ducks that can store enough energy (calories) to migrate thousands of kilometres and arrive ready to lay a clutch of eggs, and incubate them for about 30 days. One example of a capital breeder is the common eider, which averages between two and six pounds.

“Income” breeders like the far smaller blue-winged teal (weighing in at 400 grams) are unable to sustain the same kind of fuel reserves. When they arrive at the nesting grounds, they’re looking for protein- and calcium-rich foods, like invertebrates, that provide the nutrients they need to produce a clutch of eggs

Medium-size waterfowl like mallards fall somewhere between capital and income breeders. “Birds of average size usually have enough nutrients to initiate the first clutch of eggs, but they don’t have enough reserves to re-nest,” says Howerter. However, some duck species (like mallards, which are persistent re-nesters) will produce a second or third clutch if their first one is unsuccessful.

Nesting is natural – Birds, like people, experience the urge to nest before they welcome offspring into the world. Expectant bird and human parents alike can trace this feeling to the hormone prolactin. Prolactin is released into the blood stream by the pituitary gland, found at the base of the brain.

Laying a clutch of eggs – A hen’s pituitary gland will also release two hormones that stimulate egg production: follicle-stimulating hormone and luteinizing hormone. They trigger ovulation. Once a duck begins to ovulate, a drake can fertilize her egg – then things begin to take shape. “Once the ovum is fertilised the egg starts to develop. 

The yolk provides nutrients to the developing embryo and albumen (egg white) is deposited around it, followed by the shell. About seven days later, the hen will lay an egg,” says Howerter.

A blue-winged teal hen will lay between six to 14 eggs, provided she has the energy required to develop them. “Producing a clutch is very energetically expensive,” says Howerter. “In humans, it can be compared to giving birth to an eight-pound baby once a day for nine to 10 days.”

Sitting still – Once a duck has laid her eggs, she will spend nearly one month incubating them. While some ducks, like common eiders, will stay on their nest nearly continuously, other birds take more frequent breaks to eat. “But even they will lose roughly 30 per cent of their body weight,” says Howerter. In some cases, hens may abandon their clutch if conditions become unfavourable (bad weather, predators, disease).

Crack! – The eggs have hatched. Finally, mom can focus on relaxing and refueling, right?  “Not exactly,” says Howerter. Instead, she’ll help her ducklings find food high in protein and calcium, required for muscle and skeletal development. While ducklings are precocial (mobile after hatching), they still need help to find suitable habitat and food.

Bidding farewell – After 30 to 40 days, many hens will leave their broods to prepare for moulting (the process in which ducks lose their flight feathers). “The ducklings are on their own after that,” says Howerter, noting at this point young waterfowl are able to source their own food. At a month old, ducklings are also faster and stronger, making them far more difficult for predators like foxes, raccoons, red-tailed hawks and mink to catch and eat.

Back amidst the grasses, the blue-winged teal hen has hatched a healthy brood of ducklings and led them to the nearby wetland. In future years, these ducklings will return to the prairie landscape to produce their own offspring and repeat this fascinating but strenuous process of duck-rearing.

Continuing that cycle depends on a key ingredient, says Howerter. “Good habitat across Canada’s waterfowl breeding grounds is essential to overcoming the many challenges of successful reproduction for returning birds.”

Healthy and plentiful habitat. It’s the best welcome mat we can roll out for waterfowl every spring.

Julielee Stitt

Communications coordinator for Ducks Unlimited Canada.