Creationism in Crisis - A Tiny Bird Refutes Creationism - Again

Titipounamu, Acanthisitta chloris

Photo: Dr. Kristal Cain.

Titipounamu, Acanthisitta chloris

Photo: Dr. Kristal Cain.

Tiniest bird delivers evolution lesson - The University of Auckland

In case any creationists are still under the delusion that mainstream biologists are abandoning the scientific Theory of Evolution (TOE) in favour of their childish magical story involving a magic man made of nothing who magicked everything into existence out of nothing with some magic words, here is an example of how the TOE is used to understand and make sense of the observable facts.

It addresses the question of how the ability to learn and imitate sounds evolved in birds.

Basically, ornithologists had thought that birds could be divided into two groups - those which can learn sounds (parrots, songbirds, and hummingbirds) and those which can’t - and that this ability in the former group had evolved sometime after modern birds had diversified from their avian dinosaur ancestors, but the fact that a small New Zealand bird, the titipounamu or rifleman, Acanthisitta chloris, has the rudiments of this ability suggests it may have been present in the common ancestor of both groups.

In other words, the ability to learn and imitate sounds may be evidence of common descent.

Tell me all about the New Zealand bird, the Titipounamu, Acanthisitta chloris, please. The Titipounamu, also known as the Rifleman, is a small bird endemic to New Zealand, belonging to the species Acanthisitta chloris. Here's a detailed overview of this unique bird:

Classification

• Family Acanthisittidae
• Genus Acanthisitta
• Species Acanthisitta chloris

Physical Description

• Size The Titipounamu is one of New Zealand's smallest birds, measuring about 8 cm in length and weighing around 6-7 grams.
• Color Males have a bright green upper body and a whitish underside, while females are more subdued in color with a brownish-green back and lighter underparts. Both sexes have a distinctive short tail and a pointed bill.

Habitat

• Range The Titipounamu is found in forests throughout New Zealand, including both the North and South Islands. They prefer dense, mature forests but can also be found in regenerating bush and even in some urban parks with suitable vegetation.
• Altitude They inhabit both lowland and montane forests, sometimes occurring up to the tree line.

Behavior

• Feeding Titipounamu are insectivorous, feeding primarily on small insects and spiders. They forage actively, often seen gleaning insects from leaves and bark, and occasionally catching prey in mid-air.
• Social Structure These birds are often seen in pairs or small family groups. They are known for their high-pitched, rapid calls, which can be difficult to hear due to their frequency.
• Breeding The breeding season typically spans from September to February. They nest in tree cavities, including natural holes and crevices in trunks. The female lays about 2-5 eggs, which both parents help to incubate and rear. The young fledge in about 18-21 days.

Conservation Status

• Threats Predation by introduced mammals such as rats, stoats, and possums poses a significant threat to Titipounamu populations. Habitat destruction and fragmentation also impact their numbers.
• Conservation Efforts Conservation measures include predator control programs, habitat protection, and restoration projects. These efforts aim to provide safe breeding environments and reduce the impact of invasive species.

Cultural Significance

• Maori Connection The name "Titipounamu" is derived from Maori language and culture, where the bird holds significance in local traditions and folklore.

Interesting Facts

• Flight Despite their small size, Titipounamu are agile fliers. Their rapid wing beats make them resemble a rifle bullet in flight, which is how they got their English name, Rifleman.
• Longevity They have a relatively short lifespan, often living only 1-2 years in the wild, though some individuals may live longer under favorable conditions.

Observing the Titipounamu

• Where to See Nature enthusiasts can spot Titipounamu in many of New Zealand's national parks and forest reserves, particularly where predator control measures are in place.
• Best Time to See They are active year-round, but the spring and summer months (breeding season) are the best times to observe their behavior and possibly see their young.

The Titipounamu is a fascinating and essential part of New Zealand's avian biodiversity, contributing to the unique ecological tapestry of the region. Conservation efforts continue to be crucial in ensuring the survival of this diminutive yet captivating bird.

This discovery was made by biologists at the University of Auckland, led by Dr Kristal Cain, who have published their findings, open access, in the Journal Communications Biology. Their research and its significance are explained in a University of Aukland news release:

The titipounamu may have vocal abilities no one knew about, changing a chunk of evolutionary history.

Parrots, songbirds and hummingbirds can learn to make new sounds. Noone knew, but New Zealand’s smallest bird, the rifleman or titipounamu, may have a rudimentary version of the same talent.

University of Auckland research into the bird is part of a rethinking of how and when vocal learning evolved in birds.

Scientists traditionally assumed birds were split into two groups -- those which can learn sounds (parrots, songbirds, and hummingbirds) and those which can’t -- but the study published in the scientific journal Communications Biology adds to evidence challenging that assumption.

Vocal signatures of distantly related titipounamu had strong similarities if they lived near each other, the Waipapa Taumata Rau, University of Auckland research showed. Close relatives living far apart didn’t sound similar.

Most animals communicate with unlearned, innate vocalisations, while vocal learners include humans, whales and dolphins, elephants and bats.

That suggests the birds’ sounds may not be innate and may be learned from each other, according to Dr Kristal Cain, the senior author of the study, and Dr Ines G. Moran, the lead author.

Weighing the same as five or six paper clips, titipounamu live in high-altitude mature native forest, feed on insects and make high-pitched sounds inaudible to some people.

The bird is one of the country’s two surviving native wren species and a sort of evolutionary missing link between two of the most impressive learners, songbirds and parrots. Relics of Gondwana, the wrens likely existed in Aotearoa since before the islands broke away from the super continent, roughly 80 million years ago.

If New Zealand wrens are vocal learners, then it is likely that the common ancestor of parrots and songbirds was also capable of rudimentary learning. This ability in birds could have evolved millions of years earlier than we previously thought.

Dr. Kristal E. Cain, Senior author
School of Biological Sciences, And the Centre for Biodiversity and Biosecurity University of Auckland, Auckland, Aotearoa New Zealand.

Vocal learning in songbirds evolved 30-50 million years ago, scientists have estimated. But the songbirds and parrots diverged long before that – closer to 80 million years ago.

Dr Ines G. Moran

The scientists went to all sorts of lengths to gather evidence of vocal copying, such as 'vocal convergence,' where animals’ calls become acoustically similar.

First, they closely monitored the nests of titipounamu at Boundary Stream Mainland Island in the Hawke’s Bay, identifying and banding individuals and then recording more than 6,800 of the feeding calls routinely made by adult birds (parents and the parents’ helpers) bringing food to the young nestlings over three summers.

While the differences in the birds’ calls can’t be detected by most people, detailed analysis of spectrograms – “voiceprints” – revealed unique individual vocal signatures.

The researchers then acquired genetic information on the population at large.

Finally, they used advanced genetic methods to estimate how much and which aspects of the vocal signature came from genetics as opposed to the social environment. For some parameters, social environment was more important than genetics; there were similarities with a known vocal learner, the zebra finch.

The evidence from the scientists’ study isn’t conclusive but it’s strongly suggestive of “rudimentary vocal learning abilities.”

A growing body of evidence suggests we may need to stop classifying birds as either vocal learners or vocal non-learners. The ability may be much more widespread and likely exists along a spectrum.

Dr. Kristal E. Cain

Most animals communicate with unlearned, innate vocalisations, while vocal learners include humans, whales and dolphins, elephants and bats.

Titipounamu.

Photo: Ines Moran

The vocal behaviour that we were unravelling in this study is very similar to what is known as vocal accommodation in human linguistics. It’s similar to our ability to adjust our ways of speaking in different social, dialectic, or hierarchical settings – modulating our voices to better fit in certain social groups.

Dr. Ines G. Moran, lead author
School of Biological Sciences, And the Centre for Biodiversity and Biosecurity University of Auckland, Auckland, Aotearoa New Zealand.

Artificial intelligence, custom engineered nest RFID (radio frequency identification) readers, and custom-made computer analysis tools were all part of the study, which spanned bioacoustics, genetics, behavioural ecology, and field biology.

The scientists thank the mana whenua of the Maungaharuru region, the University’s engineering team, the Department of Conservation, AgResearch, and the Centre for eResearch.

Technical details and background to the research are given in the team's open access paper in Communications Biology:

Abstract
Despite extensive research on avian vocal learning, we still lack a general understanding of how and when this ability evolved in birds. As the closest living relatives of the earliest Passeriformes, the New Zealand wrens (Acanthisitti) hold a key phylogenetic position for furthering our understanding of the evolution of vocal learning because they share a common ancestor with two vocal learners: oscines and parrots. However, the vocal learning abilities of New Zealand wrens remain unexplored. Here, we test for the presence of prerequisite behaviors for vocal learning in one of the two extant species of New Zealand wrens, the rifleman (Acanthisitta chloris). We detect the presence of unique individual vocal signatures and show how these signatures are shaped by social proximity, as demonstrated by group vocal signatures and strong acoustic similarities among distantly related individuals in close social proximity. Further, we reveal that rifleman calls share similar phenotypic variance ratios to those previously reported in the learned vocalizations of the zebra finch, Taeniopygia guttata. Together these findings provide strong evidence that riflemen vocally converge, and though the mechanism still remains to be determined, they may also suggest that this vocal convergence is the result of rudimentary vocal learning abilities.

Introduction
Most vocal animals communicate with innate vocalizations, but a few taxa are capable of vocal production learning – a behavior that provides animals with the learning ability to copy, match, or imitate sound¹. Species that vocally learn include a wide range of distantly related taxa such as cetaceans², pinnipeds³, elephants⁴, bats⁵, humans, hummingbirds⁶, parrots⁷, songbirds⁸, and although more research is needed, it appears they also include a few suboscines (e.g. bellbirds, Procnias spp⁹.), African naked mole-rats (Heterocephalus glaber)¹⁰, musk ducks (Biziura lobata)¹¹ and black-headed gulls (Larus ridibundus), among others¹². This paraphyly of vocal learners has led to many hypotheses about the evolution of vocal learning, along with a relatively new hypothesis, which suggests that vocal production learning exists along a continuum consisting of modules^1,13 – as opposed to a binary dichotomy between vocal learners and vocal non-learners (absence vs. presence). In this hypothesis, vocal production learning is made up of distinct, yet connected behavioral modules (e.g. vocal convergence, vocal matching, mimicry, and song sharing) – resulting in varying levels of vocal learning complexity (i.e., absent, limited/rudimentary, advanced)^{1,14,15,16,17}.

Birds are an excellent group to explore this hypothesis due to their diverse vocal production learning abilities. While advanced vocal learning is well established in parrots (Psittaciformes)⁷, hummingbirds (Trochiliformes)⁶, and oscine songbirds (Passeriformes)⁸, the picture is less clear for suboscines (Passeriformes) and the New Zealand wrens (Passeriformes and sister sub-order to oscines and suboscines, Fig. 1). Suboscines have traditionally been classified as vocal non-learners^18,19, but some species have been reported as vocal learners⁹, or as limited learners with a rudimentary neural circuitry related to vocal learning in oscine songbirds^14,20. As for New Zealand wrens, their vocal learning abilities have never been directly tested, and have been assumed to be nonexistent based on their simple syrinx morphology (i.e., lacking the intrinsic muscles present in vocal learners^21,22), and their basic and short call structure (i.e. lacking complex and broadcast songs^23,24,25). However, recent revisions of the avian phylogeny show that the New Zealand wrens share a close common ancestor with vocal learning parrots and oscines, and with suboscines^{26,27,28,29,30} (Fig. 1). According to the continuum/module hypotheses^1,15, this opens the possibility for New Zealand wrens to have rudimentary learning abilities. Investigating New Zealand wrens’ vocal behaviour and plasticity, and determining where this species fits into the rudimentary/vocal learning continuum hypotheses is hence key to resolve gaps in the evolution of vocal production learning in Passeriformes.

Fig. 1: Schematic phylogenetic tree with associated vocal behaviors of New Zealand wrens and other birds.

Avian vocal behaviors are categorized based on neurobiological and/or behavioral studies or anecdotes (see below) and are represented with colored rectangles. Behaviors, such as vocal production learning for calls and songs, are separated due to their distinct neurological and functional basis, which may have evolved separately^131,132. Diagonally barred rectangles indicate that, although there is some evidence for vocal production learning in this taxon, further testing is needed. When no data is available on the presence or absence of vocal production learning in a clade, vocal behaviors are represented with empty rectangles. Triangles highlight novel and previously unknown behaviors found in this current study (i.e. in the rifleman). Innate vocalizations (labeled in yellow) are present in all bird clades suggesting that they were likely present in the common ancestor to all birds. Seven bird clades vocally converge toward common group vocal signatures (labeled in black) and include oscines^41,133,134, suboscines¹⁰¹, New Zealand wrens (based on current study), parrots^44,76,135, wood-hoopoes⁷⁶, hummingbirds⁸² and penguins⁹². Two bird clades have possible rudimentary/limited vocal learning predispositions (labeled in green), the suboscines – based on neurological evidence^14,20 and New Zealand Wrens – based on the quantitative genetic model comparisons from this study. Call learning (labeled in light blue) has been demonstrated in oscines^42,51,52,53, parrots⁵⁶ and although more research is needed, it is also present in one species of gulls^12,136 and ducks^11,12 and may be present in New Zealand Wrens (this study). While song learning (labeled in cyan blue) has clearly been demonstrated in oscines^8,137 and hummingbirds^6,138, other forms of song learning have also been found in suboscines⁹ and parrots^139,140,141. This simplified subtree was derived from Jetz et al.¹⁴².

In wild and at-risk animal populations, such as New Zealand wrens, well-established approaches that enable the detection of vocal production learning abilities (e.g., cross-fostering, social isolation, deafening)^31,32,33 are often unfeasible. Alternative innovative methods are needed, such as the detection of behavioral modules and behavioral predispositions unique to vocal production learning. An example of such a behavioral module is vocal convergence – a form of vocal modification controlled and maintained over time among socially close conspecifics. To achieve vocal convergence, individuals change their unique vocal signatures toward common group vocal features, resulting in group vocal signatures^{34,35,36,37,38,39}. Vocal convergence is a particularly important behavior in the investigation of vocal production learning because it may have been a precursor of more complex forms of vocal production learning (e.g., vocal matching or mimicry)^17,36,39,40.

Another powerful tool for detecting vocal production learning is quantitative genetics as it facilitates the investigation of the role of genetics and social environment in shaping vocal behavior. In vocal non-learners, kin are expected to sound more similar due to their shared genetics⁴¹, but in vocal learners, individuals often copy sounds from distantly related social partners, eroding that similarity^{34,37,42,43,44}. Thus, if distantly related individuals sound more similar than their close kin, this could suggest that a form of vocal imitation occurs. Furthermore, according to the phenotypic plasticity continuum⁴⁵, it is possible to distinguish vocal learners from vocal non-learners, by partitioning genetics from social environment and by determining how these latter factors contribute to the phenotypic plasticity and variation of vocalizations⁴⁶. Accordingly, vocal learners are expected to have a phenotypic vocal plasticity strongly associated with social environment, while vocal non-learners are expected to show limited voluntary vocal control and display minimal phenotypic vocal plasticity associated with social environment (i.e., indicative of a stronger genetic basis of vocalizations)^45,47.

By using alternative and integrative approaches, we aim to determine whether the rifleman (titipounamu, Acanthisitta chloris), one of the only two extant species of New Zealand Wrens, has predispositions for vocal production learning (e.g., rudimentary vocal learning abilities). Among riflemen’s large call repertoire⁴⁸, feeding calls are a good candidate for this investigation. They are produced in a cooperative breeding social context by both parents, kin and unrelated helpers at nests^49,50. Vocal learning (if present) is most likely to have evolved in such a social context, in contrast to non-interactive solitary contexts. Furthermore, rifleman feeding calls are social contact calls, which are often learned in avian vocal learners, such as in parrot and zebra finches’ contact calls and the flight calls of the Carduelinae subfamily^{42,51,52,53,54}.

Here, we search for predispositions for vocal production learning in the rifleman in two ways: (1) by investigating the presence of individual and group vocal signatures and determining how genetic relatedness and social proximity influence the acoustic similarity and feeding call features of distantly related individuals living in close proximity; (2) by disentangling the genetically driven phenotypic variances of rifleman call features from their socially driven vocal counterparts using quantitative genetics, and by comparing those ratios to a vocal learner, the zebra finch (Taeniopygia guttata)⁵⁴.

An interesting, but perhaps not the most compelling evidence for evolution, but certainly compelling evidence that biologists are showing no signs of finding the TOE an inadequate model for explaining the observable evidence and predicting the outcome from experiments.

And so, quite incidentally and without effort or intent, compelling evidence against yet another claim by creationist frauds, who sell disinformation to their dupes in return for money and extremist political influence.

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