Research Archives - Page 5 of 13

23/04/201922/06/2019

Two new bird species from the unique and understudied Sulawesi region

This blog was first published on #theBOUblog. Check it out at https://www.bou.org.uk/blog-oconnell-two-new-white-eye-species-sulawesi/

The Wallacea region has always been known to be home to many unique species, with birds of paradise, giant reptiles and marsupial versions of sloths found among its many islands! The region takes its name from Alfred Russel Wallace, who along with Darwin, developed the theory of evolution from his studies of the species of Wallacea. When I first set my heart on a career as a Zoologist (a decision made with absolute certainty at age 12!) I dreamed of following in the footsteps of these great naturalists. So it is of no surprise that when I finally got around to starting my PhD many years later, I chose to study speciation (the formation of new species during the course of evolution) in the birds of Wallacea, with the hope the region still held mysteries to uncover. Our research focused on South-east Sulawesi, Indonesia. Sulawesi is a weird and wonderful part of the world, and island hopping through that region has provided me with a lifetime of unforgettable memories. It also allowed me to fulfill my dream, as in our recent paper in the Zoological Journal of the Linnean Society, we describe two new bird species from the Wakatobi Islands, an island chain off South-east Sulawesi (Figure 1).

10/04/201910/04/2019

Undergrad Thesis Collection 2019

Every year, the Trinity College Dublin Zoology, Botany, and Environmental Science moderatorship students (final year undergraduates) complete their own research projects related to their course. It has been my absolute privilege to spend time with these talented students and to watch their projects take shape. I am blown away by the dedication they show, the incredible topics they cover, and the way in which they approach their investigations. After their theses are submitted, the students hold a poster session where they present their work. From beetles to beer and back again, this year’s students have done impressive and solid work. I hope all our readers enjoy learning about these projects as much as I did! If you’d like to contact any of these students to congratulate them, offer them prizes/jobs, or learn more about their projects, most of them have included contact information. Without further ado, I’ll let them take it away!
-Maureen Williams, PhD Student, Zoology

25/03/201909/05/2019

Battle of the sexes – Niche contraction in females but not males in high density island populations

olive-backed sunbird sexual dimorphism and competition in Sulawesi, Indonesia

This blog was first published on #theBOUblog. Check it out at https://www.bou.org.uk/blog-oconnell-olive-backed-sunbird-sexual-dimorphism/

Going right back to the time of Darwin, competition has always been seen as a driver of evolution. When we think of natural selection we often think of hyaenas and lions fighting it out on the plains of Africa, or a pack of wolves hassling a bear over a carcass. Resource competition like this is a daily part of survival for most animals, with a delicate balance of power between competitors which can change in different environments. However competition for resources takes place not only between species (interspecific competition), but within them (intraspecific competition), and often this is where competition is at its most fierce. Sexually dimorphic species present a special case when studying competition in different environments. They are species where the males and females are physically different, often in body size, but also in colouration and other characteristics. Males and females in sexually dimorphic species often occupy different but interlinked ecological niches. If intraspecific competition becomes more intense within a population of a sexually dimorphic species then one sex may suffer more than the other due to being smaller. In our recent paper in Emu – Austral Ornithology we report on one such case with a niche contraction in female Olive-backed Sunbirds (Cinnyris jugularis), but not males, in a highly competitive environment on small islands. This work was carried out on the remote and understudied islands of South-east Sulawesi, Indonesia (Figure 1), where a joint team of scientists from Trinity College Dublin (TCD) and Halu Oleo University (UHO) have been carrying out research into bird evolution since 1999.

14/02/201914/02/2019

Looking beyond mean trends of environmental change

During my first week in Dublin, Ireland, I was more shocked by the countless sunny-rainy shifts within one single day than its natural beauty, although I had been warned of its fickle weather in advance. That was something totally new to me. Born and raised in a small inland town in North China, I had grown accustomed to taking for granted that a whole sunny day could be prophesised by bright morning sunlight through the window. Then I started to imagine that, if fitting a curve to the weather, the curve of my birth village would surely be much smoother than Dublin, even though the former has four much more distinct seasons. But, at that moment, I had neither realized that this thought actually reflected the difference in the temporal autocorrelation of environmental conditions in the two places nor how this could be linked to the dynamics and stability of ecosystems.

Read Marvin’s full post on the Nature Ecology & Evolution blog.

This post is based on the paper Yang et al. (2019) ‘The predictability of ecological stability in a noisy world.’ Nature Ecology & Evolution

Header photo by Brocken Inaglory on Wikimedia Commons (CC BY-SA 3.0)

07/11/201818/02/2019

Kingfisher Evolution in the Wallacea Region

Studying diversification in the Todiramphus kingfishers of Sulawesi often brought to mind the adage, ‘what is rare is beautiful’. Though I certainly also learned that rare beauties can be incredibly frustrating! While I could be guaranteed to catch my other main study taxa, Zosterops white-eyes, by the dozen in the right habitat, Collared Kingfishers (Todiramphus chloris) and Sacred Kingfishers (Todiramphus sanctus) were much more elusive. This made them maddening study species, but ensured that every time I got to grips with one was a special moment. Each bird caught was measured and had a few flank feathers taken before release. Even the most disappointing site could be made worthwhile by catching a kingfisher. In particular, I’ll never forget a particularly fetid swamp in the backwoods of Sulawesi, as I’m pretty sure all the mosquitos in the world lived there. It yielded our worst ever bird catches, but two crucial Collared Kingfishers! These moments of elation have stuck with me, and have ensured that the Todiramphus kingfishers are the study species I’m most fond of.

Darren O’Connell and Adi Karya examine birds, while being examined by passers-by. Photo by Suliman La Ode.

Continue reading “Kingfisher Evolution in the Wallacea Region”

17/08/201818/02/2019

Range extension for the Dwarf Sparrowhawk

Biodiversity monitoring work can often be disheartening. Typically, we end up documenting a decline in whatever species we are working with. So it’s always a pleasure to have the opportunity to deliver some positive news. A stroll with my collaborator Adi Karya around his university campus in Kendari city provided an unexpected opportunity to do just that. Halu Oleo University has quite a unique green space, a 65 ha patch of city forest, an island of jungle in a sea of urban development. While picking our way through a particularly muggy gully we saw the flash of a small raptor in the canopy, giving me just enough time to snap off a shot before it skulked away. Continue reading “Range extension for the Dwarf Sparrowhawk”

31/07/201818/02/2019

The avifauna of Kabaena Island

Most of us start off in ecological research for the fieldwork. I always dreamed of following in the footsteps of Darwin or Wallace, discovering species and exploring new lands. While I haven’t quite reached the level of my august peers (yet!), my PhD has allowed me to take a step on the road towards following that dream. My PhD field work involved travelling around beautiful tropical islands in remote parts of Indonesia. Tough work, but someone has to do it. We moved site every week as part of our sampling regime, working in mountains, swamps and everything in between. We stayed with local families, sometimes in hovels, sometimes in veritable palaces, often with one following the other. I find it hard to pick my favourite site, I loved them all in their own way, but if I have a favourite it’s Kabaena Island, off the south-east peninsular arm of Sulawesi. In 2016 I spent three weeks there surveying bird populations as part of joint research by Trinity College Dublin (TCD) and Halu Oleo University team. This work complemented previous research by previous TCD teams in 1999, 2001 and 2003 which led to the discovery of a new species of the Red-backed Thrush, the Kabaena Thrush (Geokichla erythronota kabaena). Continue reading “The avifauna of Kabaena Island”

20/06/201818/02/2019

Little ants under big pressure

A recent study led by Sam Ross and published in the journal Biotropica, asks how selective logging interacts with habitat fragmentation to affect ant biodiversity in a Kenyan rainforest. Read more in the blog post snippet below, or see the full blog post on the IMECO blog:

“Our recent study asks how selective logging intensity affects ant biodiversity in Kakamega forest in Western Kenya. Building on fieldwork conducted by Paco Hita Garcia and Georg Fischer ~10 years ago, we aimed to uncover how logging intensity in the past and recently interacts with habitat fragmentation to affect ant communities. We found that recent selective logging matters the most, and that ant species that lived mainly in the forest were particularly affected by logging. Our work reveals how recent logging activity may overshadow any historic impacts in this forest in Kenya. Continue reading “Little ants under big pressure”

23/04/201818/02/2019

Delicious Cuscus

Studying island bird biogeography in the tropics for my PhD has presented me with many weird and wonderful opportunities. None more so than accidentally becoming a mammologist along the way. My study region of Sulawesi, Indonesia, is home to the westernmost marsupial species in Asia, the Cuscus. Cuscus are like marsupial sloths, living life in the slow lane and spending most of their time foraging on leaves and digesting. The absence of large mammalian predators from Sulawesi means that they have few natural predators to disturb this sedate lifestyle. In a recent collaborative paper in Australian Mammalogy we report on the distribution and status of the endemic marsupials on the offshore islands of South-east Sulawesi.

Sulawesi Cuscus remain poorly studied; little is known about their ecology, the threats they face, and even their distribution within Sulawesi. The main focus of the cuscus research in South-east Sulawesi has been Buton Island, where researchers with Operation Wallacea have monitored populations for the past 15 years, revealing the Bear Cuscus (Ailurops ursinus) to be common, and providing the first evidence of the Small Sulawesi Cuscus (Strigocuscus celebensis) on the island. Both species are designated as Vulnerable (Helgen and Jackson 2015). Buton is likely one of the key sites for these species, retaining the largest tracts of lowland forest in the Sulawesi region, with 77% of the island’s 560 000ha still forested. Continue reading “Delicious Cuscus”

10/03/201818/02/2019

Firehawks: waking up to stories of the Dreamtime

Fire is an essential part of the ecology of many savannah and grassland ecosystems. In some cases, fire is the only way of removing older grasses that are no longer profitable for herbivores to consume. As well as having benefits for local ecology, grassland fires also offer great feeding opportunities. I have seen large groups of raptors and insectivorous birds gather at the fringes of bushfires in Kruger National Park, to take advantage of the animals flushed into the open by the moving fire front. In Australia, a number of raptors are frequently seen around bushfires. These birds; black kites (Milvus migrans), whistling kites (Haliastur sphenurus), and brown falcons (Falco berigora) are known as firehawks. In Malamalak, an Aboriginal language, the black kite is known as Kerrk, a reference to its call “kerrk-kerrk-kerrk“.There is an intriguing story about Kerrk:

“In the creation period or dreamtime, Kerrk stole fire sticks from the Dingo, so that he could cook the Cheeky yam. Kerrk is still attracted to fires and occasionally he can be seen carrying burning sticks from an existing fire to start more fires further away.” Continue reading “Firehawks: waking up to stories of the Dreamtime”