The Gouldian Finch… ahh – where to start!?
Truth is – I am probably a bit enamored by them! The way their colours startle you when you first lay your eyes on them… the way they hop across the river stones towards the tiniest puddle of water for a drink… the way your heart skips at the sound of their sharp “psshhh pshhh” call as they fly overhead…
Gouldian Finches (well, most finches for that matter) are some of my favourite feathered friends who have kept me passionate and excited about birdwatching. And I’m not the only one. The famous British ecologist, John Gould named the Gouldian Finch in honour of his wife, Elizabeth for their exquisite beauty when he described them in 1844.
And in northern Australia, there is exceptional diversity of finches.
In the Kimberley region (a beautiful part of north-Western Australia) where we have spent a lot of our time living and working, there are 11 species of finch. This is largely due to an abundance of 2 key resources: lots of grass seed (thanks to wide expanses of tropical savanna or grasslands) and lots of surface water (thanks to an annual monsoon season between December and March).
However, reductions in the numbers of finches and other “granivorous” or seed-eating birds were first recorded in Australia’s north in the early 1990s, especially “fussy buggers” like the brightly-coloured Gouldian Finch. Although they were once found in flocks of thousands across the savannas, the Gouldian Finch has experienced range contraction and population decline, they are now classed as nationally “Endangered”.
Similar to the story of northern Australia’s small mammals, northern Australia’s savannas appeared to be so wild and pristine… so why was its fauna disappearing rapidly with no obvious cause?
While the aviary trade certainly added pressure to these highly-sought-after “rainbow finches”, it was not the only cause of decline.
It wasn’t until some incredible scientists “banded together” (if you know, you know) to research the way Gouldian Finch responded to different conditions in order to tease apart the root cause of their observed decline. The aim of course was to use this understanding to manipulate conditions that promoted the recovery of these threatened colourful cuties.
And so began an 8-year study, based at Mornington Wildlife Sanctuary in the central Kimberley savannas. Finches of three species (the threatened Gouldian and the more abundant Long-tailed and Double-barred Finches) were captured: their condition was checked, a blood sample was taken and a metal ring was placed on their leg before they were released.
The environmental conditions and fire history where each bird was captured were also noted. This is because in northern Australia, “right way” fire is an important component of healthy savanna ecosystems. And without it, changed fire patterns have driven biodiversity loss across many taxa throughout this habitat.
Overall, a mighty 3630 finches – 1094 Gouldians, 1542 Long-tails and 1012 Double-bars – contributed to this study – a massive data collection effort to obtain this sample size.
But what did they tell us?
Well, the results of this project ultimately found a strong correlation between finches and fire. Across each species, birds living in areas of good fire history (smaller, less intense, less frequent burns) had lower levels of stress hormones in their body than birds in areas of poor fire history (larger, more intense, more frequent burns). BUT, what was MOST fascinating was that when the fire history of an area improved over time, the stress levels of birds decreased as well.
Is your mind blown? If not, it should be!
As birds are less stressed in areas of good fire history (likely because they have more resources) this means they are more likely to breed in these areas.
This means that if we can improve the fire history of an area, we can entice these birds back into the landscape – naturally – and increase their population size as they breed.
From a conservation perspective: this is gold. We can protect our precious biodiversity, including threatened species like the Gouldian Finch with nothing but good fire management across the landscape. We can use fire to bring them back from the brink of extinction over time.
Good, consistent fire management is really the key to how we can save granivorous birds like the Gouldian Finch into the future.
But if you’re like me, at this point, you might still be wondering: if all 3 finches had similar stress responses to fire, why is only the Gouldian Finch endangered?
And the answer to this lies in the ecology of the Gouldian Finch. As we mentioned at the top of the article: Gouldian’s are basically “fuss pots”.
That’s right –
While all the other finches are happy munching any old grass seeds, the fussy Gouldian’s preferentially target protein-rich grasses like native annual Sorghum which are only available through the dry season. When this seed supply is exhausted, they must switch to other protein-rich seeds like spinifex, which takes 3 years to mature.
While all the other finches are happy mixing and matching whenever they have enough resources, the fussy Gouldian’s prefer breeding over the wet season. In the lead up to this period, they rely on those spinifex seeds as their Sorghum isn’t available.
And, while all the other finches are happy to spin together a basic domed grass nest just about anywhere, the fussy Gouldian’s insist on nesting hollow trees. But not just hollows in any tree, of any size or in any place. That’s right, they have standards these Gouldian’s (don’t you know it) – and they certainly won’t settle for just any old hole.
While these “fussy preferences” were originally a great thing – they would have driven the species to diversify and become such a beautiful, colourful creatures over many thousands of years and fill their unique possie or niche. But when conditions change abruptly, as they did when fire patterns dramatically shifted across northern Australia, the fine balance and timings these birds relied upon for their resources were no longer aligned.
The problem is that “wrong way fire” (frequent, intense, hot burns) takes out grasses including spinifex (which don’t have an opportunity to mature and produce seed) and trees (including those with hollows) which are both resources that Gouldian’s rely on for breeding success.
When it comes down to it, the “fussiness” or specificness of Gouldian’s lowers their resilience to changes in their environments and is one of the main reasons they became so endangered so quickly.
Luckily, understanding the drivers of their decline (thanks to the ecologists who conducted this incredible research project) is the first step towards reversing them and saving species like the Gouldian Finch to ensure they can thrive once again into the future.
The results we discussed in this post were published by the incredible Dr Sarah Legge, Dr Stephen Murphy and colleagues. It is available to read and download for free on Research Gate here so definitely check that out!
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