Amy Whitehead's Research

the ecological musings of a conservation biologist


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Wildlife Wednesday: Tomtit

The tomtit (Petroica macrocephala) is a small passerine bird in the Australasian robin family (Petroicidae). Also known as miromiro, or historically the great-headed titmouse, tomtits are endemic to New Zealand. Weighing in at only 11 grams, tomtits are one of the smaller species of New Zealand birds (the lightweight record goes to the rifleman at a mere 6 grams). But what they lack in size they make up for in character. They are common throughout New Zealand and live in shrubby and forested areas, where they typically perch on a branch or tree trunk to watch for flying insects. Once spotted, they will flit out and snatch up the target before resting on the next perching spot. You can often attract a tomtit into photographing range by imitating their call and then stirring up the leaf litter to disturb insects into the air. As kids we used to imitate bird calls by rubbing a piece of polystyrene on a wet glass jar and would be rewarded with tomtits perching on our packs or boots while they scanned the air for insects.

Tomtits have played a special role in one of New Zealand’s conservation success stories, acting as surrogate parents for a number of critically endangered Chatham Island black robin chicks. Black robin numbers dropped to just five individuals in 1980 due to predation by introduced mammals. With only one female (Old Blue) remaining, a dedicated team of conservationists devised a cunning plan to rescue the species by eliciting the help of the humble tomtit. Each year the team would remove the first clutch of eggs from Old Blue’s nest and place them in a tomtit nest. The unsuspecting tomtits raised the chicks and Old Blue would lay a second clutch of eggs. This cross-fostering was so successful that some of the first fostered chicks grew up thinking they were tomtits! Some careful tinkering with the techniques produced robins that thought they were robins and there are now ~250 black robins on two islands in the Chatham Islands.  All thanks to Don Merton and his team of dedicated conservationists and tomtits!

Wildlife Wednesday: Dobsonfly

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DobsonflyGo swimming in a stony bottomed stream in New Zealand and you might just find yourself toe to face with a toebiter or dobsonfly larvae (Archichauliodes diversus).  Looking like they have stepped straight from a B-grade horror movie, dobsonfly larvae are New Zealand’s largest freshwater insect reaching up to 5cm.  They have strong jaws, capable of giving you a good nip, but they prefer to dine on other stream invertebrates.  The “legs” that give them a centipede-like appearance are actually large gills. They can survive periods of time out of the water and are often found in small cavities dug into the mud.

However, just like the ugly duckling and the swan, this story has a pretty ending.  The adults, like the one above,  have a wingspan of up to 8cm and are pretty spectacular insects.

Wildlife Wednesday: Kōwhai

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Kowhai flower

The kōwhai (Sophora spp.) is a New Zealand tree legume that typically grows in open areas and along the edge of streams and lakes.   The name kōwhai comes from the Māori word for yellow – a reference to their prolific flowers and small pea-like seeds.  One of NZ’s most iconic plants, they flower from July to November and are an important source of nectar for native birds, particularly tui and bellbirds.  They are a common garden plant and most children I know spent time trying to get the seeds to grow by throwing them in boiling water or attacking them with sandpaper (okay I may have grown up in a strange neighbourhood but these are actually the best techniques for breaking the tough outer coating of the seed to get them to grow).   However, almost all parts of the tree are poisonous to humans, so don’t be tempted to take a nibble!

While New Zealand doesn’t have an official national flower, kōwhai would do pretty well in a floral showdown.  Indeed, kōwhai flowers are one of only two plants to make it onto New Zealand coins, featuring on the New Zealand 2c coin from 1967 to 1990 (the other being the silver fern on the 1c and $1 coins).  They also featured on a 3D (as in threepence, not three-dimensional) stamp released in 1960 and the 2.5c stamp when NZ converted to decimal currency in 1967.  Apparently they have also been immortalised in folksong, although I think this may have been popular a little before my time.

Wildlife Wednesday: Black-fronted tern

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Black-fronted tern

A few years ago I did some contract work surveying nesting populations of river birds on the Waimakariri River in New Zealand.  We walked along the river bank identifying and counting birds as part of an annual census to look at populations trends over time.  We also spent a lot of time leaping in and out of a moving jetboat onto tiny patches of gravel in the middle of the river.  That led to some heart-stopping moments!

One of the more abundant species we saw was the black-fronted tern (Sterna albostriatus).  These guys nest in colonies and tend to mob anyone or anything that gets too close, including well-meaning scientists!  Which makes the counting process somewhat difficult – “Have I already counted the one wheeling around the top of my head or is that a different one?”! Black-fronted terns only breed in the eastern regions of  New Zealand’s South Island and are usually found nesting along braided rivers.  Nests are very basic, with the eggs laid among the river gravels.  Black-fronted terns feed on freshwater fish, invertebrates and worms.  Unfortunately their numbers seem to be declining, mostly likely due to predation by introduced mammals and loss of habitat.

Wildlife Wednesday: Praying mantis

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Praying mantis

Yesterday, a couple of colleagues and I watched a standoff between a praying mantis and a magpie lark outside our building.  Needless to say, the magpie lark eventually won but the praying mantis definitely gets bonus points for standing up to someone many times its size.

It reminded me of watching a standoff between a praying mantis and a honey bee a few years ago in my garden in Christchurch.  I was hanging out my washing when I spotted the praying mantis attempting to catch one of the many honey bees visiting the lavender bush.  It eventually grabbed one but it took some time before it was able to manoeuver it into a safe position for eating!

Wildlife Wednesday: Whio ducklings

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ducklings

These whio (pronounced “fee-0”) ducklings were just a few days old when I took this photo.  They were some of the lucky ones, hatching in a river valley where introduced predators were kept at low numbers due to the hard work of Department of Conservation staff (who seem to be as threatened as the species they protect).  All of eggs and ducklings just over the hill where there was no predator control got munched by hungry stoats!

I know I’ve featured whio before on Wildlife Wednesday (the inaugural post in fact) but I have a special place in my heart for these bluest of blue ducks (and a lot of photos), having spent 5 years of my life working with them.  March is Whio Awareness Month and I had great intentions of writing an enthralling post about the plight of the whio and the work that’s bring done to protect them. But it’s the end of March already and I have a week full of meetings and deadlines, so it will have to wait for another day. But luckily the good folk at the Department of Conservation and Whio Forever have been busy telling their stories.  Head over to the Whio Forever website to learn more about project – a partnership between the Department of Conservation and Genesis Energy.

Related articles

WHITEHEAD, A., EDGE, K-A., SMART, A., HILL, G., & WILLANS, M. (2008). Large scale predator control improves the productivity of a rare New Zealand riverine duck. Biological Conservation, 141 (11), 2784-2794 DOI: 10.1016/j.biocon.2008.08.013

WHITEHEAD, A., ELLIOTT, G., & MCINTOSH, A. (2010). Large-scale predator control increases population viability of a rare New Zealand riverine duck. Austral Ecology, 35 (7), 722-730 DOI: 10.1111/j.1442-9993.2009.02079.x

I should also note that this is my first post to be posted to the Research Blogging blogroll.  I wonder if this will help to make whio more popular than my most popular post so far about kakapo?

 

Wildlife Wednesday: Mount Cook Buttercup

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This beautiful white flower is often called the Mount Cook lily.  However, it is actually a member of the buttercup family (Ranunculus lyalli).  Endemic to the South Island of New Zealand, it is found in the alpine zone between 700 to 1500 m above sea level.  Plants grow up to a metre in height and have waterlily–like leaves, hence the frequent misnaming.  Flowering occurs in late spring and early summer, with flowers reaching 5-8 cm in diameter, making it the world’s largest buttercup species.