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lunes, 11 de julio de 2011

Mist nets, maggots, and moisture in roots

Here at Laguna Blanca we have finally come out of the prolonged cold spell we were enduring. It’s nice to have the sun back.
Greg Goodfellow’s investigation into aggressive reactions among white-rumped tanagers (Cypsnagra hirundinacea) is now in full swing. Each morning before first light he heads out onto the Cerrado to set up so that he can begin taking data as soon as his birds wake up. The dummy birds are also now making an appearance but there were a few slip ups when practicing launching them into trees.
Unfortunately Greg reported today that he thinks one of the females from one of his groups might have died. He did not see her and only the male was calling back to his vocal experiments. As sad as this is Greg may well be able to make something positive out of this change in demography. Having one of his groups with only one adult will provide an interesting opportunity for comparative analysis. However, perhaps she will return tomorrow.

Georgina Snelling begins her fieldwork tomorrow. Over the last few days she has been ‘keying out’ all of the species that she needs to be familiar with and able to identify. We also took a drive through all of the Cerrado to locate and finalise where she will measure out her plots so that she can begin surveying and recording the botanical dynamics of this little studied ecosystem. After some GPS training tomorrow morning she will be ready to launch the practical side of her study. Seeing as she has had her head in books for days now I think Georgina is looking forward to getting out in the field and executing her research.

Aimme Oxley’s research into the affect of disturbances on small mammal abundance and diversity has also been successfully launched. Her first capture-mark-recapture session was 6 days ago and she appears to be getting a healthy amount of individuals and data. As she began trapping while we still had the cold weather Aimme was concerned the captive animals would get too cold. Therefore she placed a good amount of bedding in each of her 260 traps.
Sex differences is one of the areas Aimme will compare. However these animals can be difficult to sex so Project Coordinator (and experienced small mammal trapper) Karina Atkinson had a session in the field with Aimme to teach her how to properly sex individuals. This was important to avoid mistakes in her data.

Behaviour among Cyanocorax chrysops (plush-crested jays)

My first paper for publication on the Plush-crested jays is under way. After this initial publication the project will move on to address more complex behavioural aspects of these birds. In order to investigate complex social dynamics each individual of each group will need a leg ring to distinguish themselves from others. This means I have to catch them. I was not looking forward to this task. Although hardly studied, these jays are regarded as having a very high level of intelligence. In fact in terms of their brain to body size ratio (a common way of assessing intelligence) Plush-crested jays are on par with great apes. This is why I wasn’t looking forward to trying to catch them. Nevertheless I though I would give it a go. With help from volunteers Jaime and Claire, and intern Aimme, we set up two mist nets in areas I regularly see the jays fly through. Then I played a series of vocalisations to attempt to attract them over. It certainly got their attention as 6 individuals turns up but, unfortunately, they did not take the bait and fly into the nets. Instead they proceeded to tease me for a couple of hours. Flying low and close to the net they would dip up or down at the last second to miss getting caught. Now I will probably have to switch to baiting cages where the door shuts when the bird pecks at the bait. Lets see how much success I have with that.
I have also started to try and cultivate some maggots. Not a nice job but I need them for the feeding stations. One of results that have come from the study thus far is that they are primarily insectivores. This may explain why they were not interested in my potato peelings. The battle of wits between man and jay continue.

Social and ecological factors among Clyomys laticeps (broad-headed spiny rat).

Initial results are in on the bush we suspect may be important to Clyomys. I have excavated 5 root samples from 5 of these bushes. As soon as I had the roots out they were put into sealable plastic bags. This was to prevent all the moisture from escaping. Once back at camp I weighed all the samples to get the weight of them when they are still holding water. Then I placed all the samples on a baking tray and put them in the oven on a low heat. I left them for 3 days so that all of the moisture would be taken out of the roots. After the drying period was finished I weighed all of them again to see what the differences was and to calculate what percentage of the roots are made up from water. Now, although the percentage of water in these roots was high – 49% - they contained only 2% more water than two other species I also tested. This means we need to look at other variables to try and work out what it is that is attracting Clyomys. So if we can reject our hypothesis that it is water content that attracts clyomys we will then start looking at nutrient levels.

Until next time I'll say goodbye.

Best Wishes,


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