PixtRoup

13/01/2022

Scientists devised a cheap, ingenious trick to save this bird from a blood-sucking maggot – and it works brilliantly
Saving endangered species from extinction is a challenging job that requires creative, affordable and effective interventions. In a rare good news story for conservation, we came up with one such method.

We want to save the forty-spotted pardalote – an extremely rare Tasmanian bird about the size of a ping pong ball. The few remaining individuals are at risk from an unusually harmful threat: blood-sucking fly larvae.

These parasitic flies search out the nests of pardalotes to feed on their defenceless young. The moment a pardalote chick hatches from its egg, the fly maggots burrow into its skin to drink its blood. The parasite kills nine out of every ten chicks in some areas.

We needed a way to ward off the parasites. As our new research shows, we made one – using chicken feathers and everyday items you’d find in any hardware store. The results show that with a bit of creative thinking and expert knowledge, vulnerable species can be protected.

A person holding forty-spotted pardolotes
Forty-spotted pardolotes are largely extinct on mainland Tasmania. Author supplied
An imperilled songbird
Forty-spotted pardalotes are olive-green songbirds with two rows of white dots along their wings. Deforestation has caused their local extinction across much of mainland Tasmania. The birds survive mostly on islands off the east coast in numbers that vary according to habitat quality.

They forage predominantly in the foliage of white gums (Eucalyptus viminalis) for manna, a sweet crystallised form of tree sap. Many Australian birds feed on manna, but forty-spotted pardalotes are unique because they “farm” it – using their beaks to make tiny nicks in leaves and stems to stimulate manna production.

But parasitic flies are threatening the survival of these remarkable little birds. The maggots of these flies, known formally as Passeromyia longicornis, bore into exposed skin of featherless chicks and feed on their blood. Unsurprisingly, as the maggots grow fat, the chicks suffer and usually die. Small birds are killed quickly when infested with large numbers of blood-sucking maggots.

Extracting a Passeromyia longicornis maggot from the chick of a common starling.
A novel solution
We wanted to find an effective way to help protect pardalotes from fly-strike. The solution also needed to be cheap, to improve the odds that land managers can help pardalotes over large areas in the long term.

Using creative thinking and our detailed knowledge of pardalotes, we devised a plan.

Read more: Birdwatching increased tenfold last lockdown. Don't stop, it's a huge help for bushfire recovery

Pardalotes love to make a soft, warm nest lined with stray feathers of other birds they find on the forest floor. But finding feathers is hard, time-consuming work. We decided to supply those feathers, but with an added bonus.

We took sterilised chicken feathers (available in pet stores for canaries to build their nests) and laced them with a bird-safe insecticide that would ward off the parasites. Using scrap wire, duct tape and round plastic trays (the kind used under pot plants), we built “self-service” feather dispensers and deployed them in the forests where pardalotes were building nests.

A feather dispenser built by the authors.
A feather dispenser built by the authors. Author supplied
It didn’t take the pardalotes long to find this bonanza of free building materials – our dispensers were as busy as the toilet paper aisle during a pandemic! Some birds built their nests mostly out of our medicated feathers.

And now for the best part: the survival of chicks dramatically improved in the nests built with insecticide-treated feathers. On average, 95% of chicks from these birds survived, compared with only 8% of birds that used feathers without insecticide.

This more than tenfold increase in nest survival came with very little effort on our part. We just provided the feather dispensers, and the pardalotes did the rest.

Forty-spotted pardalote using insecticide-treated chicken feathers collected from a dispenser to construct its nest.
Understanding the species
Parasites can become an existential threat when the populations of their hosts become very small. But it’s important to note that parasites are a natural part of the ecosystem and have their own intrinsic value. Eliminating them entirely can create unexpected new problems – and that is not our aim.

Read more: What 'The Birdman of Wahroonga' and other historic birdwatchers can teach us about cherishing wildlife

Passeromyia maggots have been recorded in other small birds in our study area. This means there are plenty of other more abundant host birds for the flies to feed on, without adding to the problems that endangered forty-spotted pardalotes already face.

Our work has shown that by understanding how species live, it’s possible to exploit their natural behaviour to provide targeted protection from threats such as parasites.

Combining good ecological data with clever problem-solving is a crucial skill for natural resource managers. Managing the global extinction crisis will require more innovative solutions like this.

13/01/2022

Women have disrupted research on bird song, and their findings show how diversity can improve all fields of science
Americans often idealize scientists as unbiased, objective observers. But scientists are affected by conscious and unconscious biases, just as people in other fields are. Studies of birds’ vocal behavior clearly show how research approaches can be affected by the people who do the work.

For more than 150 years, dating back at least to Charles Darwin’s writings on sexual selection, scientists have generally considered bird song to be a male trait. The widely accepted view was that bird songs are long complex vocalizations produced by males during the breeding season, whereas such vocalizations in females are generally rare or abnormal.

But over the past 20 years, research has shown that both males and females in many bird species sing, especially in the tropics. For example, our group has studied female song and male-female duets in Venezuelan troupials, a tropical species that sings year-round to defend territories. And we have studied female song in eastern bluebirds, a temperate species in which females sing to communicate with their mates during the breeding season.

Recent findings have shown that female song is widespread, and it is likely that the ancestor of all songbirds had female song. Now, rather than asking why males originally evolved song, the question has become why both sexes originally evolved song, and why females have lost song in some species.

In a recently published study, we reviewed 20 years of research on female bird song and found that the key people driving this recent paradigm shift were women. If fewer women had entered this field, we believe that it likely would have taken much longer to reach this new understanding of how bird song originally evolved. We see this example as a powerful demonstration of why it’s important to increase diversity in all fields of science.

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ListenMale and female troupials duetting in Puerto Rico
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New voices lead to new perspectives
Traditionally, white men working in countries of the Northern Hemisphere have conducted much of the research on bird song. Researchers in countries such as the U.S., Canada, England and Germany have focused much of their work on migratory birds that breed in the north temperate zone.

But starting in the 1990s, new research began to contradict this view. Studies pointed out the bias toward temperate zones in previous work, and indicated that in the tropics, females of many species are prolific singers. Researchers began to study how female birds use their songs, how females learn songs and why females in some species join their mates to sing precisely coordinated duets.

We noticed that women had written many of the key papers on female song published in recent years and wondered whether this was a general trend. To see whether women were significantly more likely to publish about female bird song than men, we identified all papers with “female song” in the title or abstract that had been published in the last 20 years. Next we assembled a set of papers generally published in the same journals in the same years, but focused on “bird song” more broadly.

Pair of Venezuelan troupials
Male and female troupials. Both sexes are elaborately colored, and both sexes sing. Karan Odom, CC BY-ND
For each of these papers we determined the genders of all authors, including the first author, middle authors and final author. Final authors frequently are the senior authors – for example, research group leaders.

Focusing on first authors, we found that 68% of female song papers were written by women, whereas only 44% of the bird song papers were written by women. Therefore, men were 24% less likely to study female song than bird song. Conversely, women were 24% more likely to study female song.

Middle authors on female song papers were also slightly skewed toward women. However, last authors were much more commonly men for both female song and bird song papers. In other words, the team leaders on these projects were still more likely to be men.

For female song studies, 58% of last authors were men. In our view, although ornithology is now a relatively gender-balanced field, more women need to be promoted into senior leadership positions, so that they can lead key decisions on research directions, funding and student projects.

Female northern cardinals sing along with males and have many different calls.
Diverse perspectives help drive scientific progress
A major goal of our study was to recognize and promote the diverse perspectives of researchers with different backgrounds and identities. However, we felt it was crucial for our study to look back at least 20 years, since that was the time frame over which this key paradigm shift occurred. Many authors from that far back would be difficult to contact directly for a variety of reasons.

In the future, allowing authors to self-identify for studies of gender and authorship in a range of fields would likely produce more correct gender data and allow researchers to identify as nonbinary or non-gender-conforming.

Our case study on bird song provides dramatic evidence that who researchers are, where they are from and what experiences they have had influence the science that they do. More diverse groups of researchers may ask a broader range of questions, utilize more varied methods and tackle problems from a wider range of perspectives.

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Gender is just one aspect of identity that could influence topics, conceptual approaches and specific methodologies used in a wide range of scientific disciplines. Many other factors, such as race, ethnicity, geographic location and socioeconomic standing, could also have important impacts on scientific research.

Recent events have vividly illustrated the effects of racial biases in areas ranging from criminal justice to outdoor recreation. Our study shows why it is important to address racial, gender and other biases to improve the outcomes of research, teaching and outreach at colleges and universities around the world.

Casey Haines, a recent undergraduate student at the University of Maryland, Baltimore County, was lead author of the study on which this article is based. Michelle Moyer, a PhD student at UMBC, helped with this work.

13/01/2022

Hard to spot, but worth looking out for: 8 surprising tawny frogmouth facts
The tawny frogmouth is one of Australia’s most-loved birds. In fact, it was first runner-up in the Guardian/BirdLife Australia bird of the year poll (behind the endangered black-throated finch).

Tawny frogmouths are found throughout Australia, including cities and towns, and population numbers are healthy. We’re now in the breeding season – which runs from August to December – so you may have been lucky enough to see some pairs with chicks recently.

Here are eight fascinating things about tawny frogmouths that you might not know.

A Tawny Frogmouth and its chick.
You might have been lucky enough to see a tawny frogmouth chick recently. Carol Smith, Author provided
Read more: What Australian birds can teach us about choosing a partner and making it last

1. They are excellent parents
Tawny frogmouths are excellent parents. Both males and females share in building the nest and incubating the eggs, generally one to three. The eggs take 30 days to hatch, with the male incubating during the day and both sexes taking turns during the night.

Once hatched, both parents are very involved in feeding the fledglings. A young bird’s wings take about 25 to 35 days to develop enough strength for flight (a process known as “fledging”).

2. They mate for life
Tawny frogmouths pair for life. Breeding pairs spend a great deal of time roosting together and the male often gently strokes the female with his beak. Some researchers report seeing tawny frogmouths appear to “grieve” when their partner dies.

For example, renowned bird behaviour expert Gisela Kaplan tells of rearing a male tawny frogmouth on her property then releasing it to the wild. It found a female mate and raised nestlings. One day, the female was run over on the highway; Kaplan recognised its markings.

She found the male “whimpering” on a nearby post. Kaplan reportedly said: “It sounds like a baby crying. It affects you to listen to it.” According to Kaplan, the male stayed there for four days and nights, and did not eat or drink.

A pair of Tawny Frogmouths in a tree.
Breeding pairs spend a great deal of time roosting together. Shutterstock
3. They’re not owls
Although tawny frogmouths are often referred to as owls, they are not. But they do resemble owls with their large eyes, soft plumage and camouflage patterns, because both owls and frogmouths hunt at night. This phenomenon (where two species develop the same attributes, despite not being closely related) is called “convergent evolution”.

Unlike owls, tawny frogmouths do not have powerful feet and talons with which to capture prey. Instead, they prefer to catch prey with their beaks. Their soft, wide, forward-facing beaks are designed for catching insects. They will also feed on small birds, mammals and reptiles.

4. They are masters of disguise
Tawny frogmouths are extremely well camouflaged and when staying statue-still on a tree branch they appear to be part of the tree itself. They often choose to perch near a broken tree branch and thrust their head at angle, further mimicking a tree branch.

A tawny frogmouth sits still on a branch.
Tawny frogmouths are extremely well camouflaged and when staying statue-still on a tree branch they appear to be part of the tree itself. Shutterstock
5. They make strange noises
Tawny frogmouths are quite vocal at night and have a range of calls from deep grunting to soft “wooing”. When threatened, they make a loud hissing sound. Their vocalisations have also variously been described as purring, screaming and crying.

6. They can survive extremes
In colder regions of Australia, tawny frogmouths are able to survive the winter months by going into torpor for a few hours. In this state, an animal slows its heart rate and metabolism and lowers its body temperature to conserve energy.

On very hot summer days tawny frogmouths will produce mucus in their mouths which cools the air they breathe in, thereby cooling their whole body.

7. They need old trees
It’s not that uncommon to see tawny frogmouths dead on the road; they often flit across the road chasing insects at night and can be hit by cars.

Tawny frogmouth populations are holding relatively steady, but there is a shortage of old trees for nesting. They especially like trees with old branches as they mimic old branches and stick out like sore thumbs on young branches.

When one NSW council chopped down a suburban tree that a tawny frogmouth pair had reportedly used for years as a nesting site, one of the birds was photographed sitting on a nearby woodchipper — a poignant image.

8. They’re not good at building nests.
Tawny frogmouths are pretty slack when it comes to nest building. They simply dump twigs and leaves in a pile and that is it. Chicks and eggs have even fallen out of the nest when parents are swapping brooding duties.

13/01/2022

13/01/2022