Nesting Logged Birds

Left: Aldina (3Y+) is nesting on a ruin amid cork oak grassland. She is the left hand bird on the nest marked by the arrow.
Right: The logger has settled below Aldina's feathers, only her blue colour rings (just visible in this shot) ID her.

Studying the GPS positions of the logged birds has allowed me to work out where they might be nesting –especially now the birds are spending more time at their nests because the breeding season is getting underway.

Brutus (3W+) head down tidying his nest in a Eucalyptus tree

Part of my fieldwork involves visiting the nests to gather data. It is great to see the logged birds are all doing well and are apparently completely unaffected by their logger back-packs. These quickly sunk down into the feathers, which (most importantly) minimizes drag in flight but also keeps the loggers dry and safe from exposure to the elements. The loggers are not even visible as a hump on the storks backs! Only the blue colour rings on each leg indicate to me which storks are my logged birds.

Excuse the quality of my logged bird photos. They were taken through my telescope and Nuno was photographed in heavy rain. Most of the logged birds are in nests too high to view in to, with the exception of Aldina. She is in a colony of 10 nests had 3 eggs when I visited - and may even lay more eggs. More updates on her progress and hopefully photos of her chicks as the season progresses.

Nuno (37+) hunkered down in heavy rain on his nest 

in a Eucalyptus tree. Although other members of his 

colony have started laying it is likely that Nuno does 

not yet to have eggs because he was not incubating 

them, despite the rain.

An Early Easter Egg Hunt

Another great day in my office!

 

I hear it is predicted to be the coldest March weekend for 50 years and snowing in most of the UK at the moment? 

UK readers skip to the next paragraph immediately…. 

 

 

Wild flowers in an olive grove on the Spanish border

            ….or weep as I describe the blue skies and warm sun in Portugal; how my spring fieldwork is not on landfill sites but mostly consists of wandering in sunny fields bright with spectacular purple, yellow and white drifts of wild flowers. The blossom is out on the fruit trees, swallows skim low over the gently nodding heads of vipers burgloss, lavender, rocket, lupins, dwarf iris and chamomile; and my footsteps through the long grass send butterflies scattering in to the air: Whites, Painted Ladies, Swallowtails and Blues. Did you know that all the UK’s Painted Lady butterflies are migrants? Neither these nor most of the swallows will be arriving in the UK for quite some time yet… 

This is Portugal at its finest, before the hot summer sun browns the meadow grass.  

First prize in my Easter egg hunt: shell plus contents!

Safe to read now...

It is not all paradise though. As well as tracking the logged birds (the subject of my next blog post) I have been visiting stork nests to see how many eggs have been laid, and to collect regurgitated pellets and egg shell -2 Easter egg hunts in one! 

Despite the wild flowers, the meadow directly below a stork’s nest is not a pretty sight –covered in smelly unsavoury poo and debris that I rummage through. Hunting through brambles, wildflowers and stands of tall nettles, eggshell is usually well hidden. Is that speck of white nestled deep against the soil a fragment of eggshell? Usually it is just light reflecting off a eucalyptus leaf, or a poo splatter, litter, a white stone or a bleached snail shell…. The anticipation of the hunt keeps me interested for hours!  

Similarly viewing in to nests to see how many eggs have been laid is like sharing a secret with each stork!

How many eggs have you laid so far...?

Storks usually lay 1-6 eggs but only manage to rear 1-4 chicks. Last year bad weather resulted in very bad breeding success. Keep following my blog to see if this year is a good or bad year for the storks breeding in Portugal.

Im a bit wildflower obsessed after the long UK winter: Rocket, lupins and Cork Oak logs

Field Season Begins!

Like planning a military campaign! Maps of all my colonies

Tomorrow I leave for not-so-sunny Portugal! It has been raining a lot there recently but hopefully this will not make the tiny country tracks too difficult to drive down because I want to visit the colonies of all the logged birds.

As you can see from the picture I have been studying high resolution maps marking the location of stork nests to see if any are likely to correspond to the nests of logged birds. I love maps so having many of them spread out across the table in front of me is right up my street. It feels more like being an explorer or planning a historic sea battle than putting the finishing touches to field work!

Next post from Portugal. I shall be visiting colonies at first and last light to see which nests are occupied and also tracking logged birds. Keep checking the BTOs website and my blog for the latest stork news!

Thanks to all of you who have donated to Support a Stork so far, your funds are hugely appreciated!

Forensic Ecology

Gorgeous blue Roller feather samples plus cleaning chemicals

I use stable isotopes of Hydrogen, Carbon and Nitrogen from feathers and claws to determine if a bird wintered in Iberia or Africa. This is the bit of my research that non-scientists least understand, so how does it work?

In a nutshell a stable isotope is one of 2 or more naturally occurring forms of the same element. They demonstrate the same chemical properties and vary only in the number of neutrons in the nucleus. This means the only difference between them is a slight variation in weight. They are stable because they do not decay over time like radioactive isotopes. In food webs the heavier isotope is usually less common than the lighter form and I measure these tiny differences in weight ratios in a mass spectrometer.

Samples are weighed out into tin capsules and folded very small

Fractionation. Various naturally occurring biochemical processes (eg rainwater evaporation, body metabolism) alter the ratios of stable isotopes at the base of the food chain (fractionation) and these isotopic signatures are taken up by all species through diet and drinking water and become permanently fixed in hair, nails and feathers after growth. This means the stable isotope ratios in my feathers and claw samples reflect the values in the local food web where they were grown and are unchanged when a bird migrates to a new, isotopically distinct location. From this inferences can be made about the location where the feathers were grown.

My Analysis. At the moment I am simultaneously analysing Carbon (13C/12C) and Nitrogen (15N/14N) -expect a blog about Hydrogen (2H/1H) later. Nitrogen is used to distinguish trophic position in the food chain and to detect changes between marine and freshwater diets; not so applicable for my birds so I am more interested in Carbon.

The 2 furnaces for the mass spectrometer. The red 'Vecstar' furnace for C/N next to the 'Costech' furnace used for H

Forensic Ecology. Carbon isotopic ratios indicate what sort of habitat the feather/nail was grown. This is because C₃ and C₄/CAM photosynthetic pathway plants fractionate Carbon isotopes differently by each using a different enzyme to grab CO₂ out of the air at the first step of photosynthesis. Most temperate latitude plants are C3 pathway species (eg wheat, potatoes). C4 plants (eg sugarcane) dominate in tropical and subtropical latitudes and have higher d13C ratios than C3 pathway plants. This means I can tell what sort of plan life was at the base of the food chain where the feather was grown and this helps me decide whether the bird spent the winter in a temperate or (sub)tropical region.

It is all pretty amazing! –but not without various problems in data interpretation which I am sure I shall go in to (read: rant about) at some point!

The output screen: 2 square peaks of reference gas, then a small Nitrogen peak. The jump to Carbon (more visible as a line in the top graph) then a taller Carbon peak and 2 square reference peaks -the second just being produced. The Carbon peak is taller because feathers contain more Carbon than Nitrogen.

Storks in the News

Science Daily have published a news article about my storks:

http://www.sciencedaily.com/releases/2013/02/130227085845.htm

Enjoy!