Thread by @Camilo_Carneiro

The second field season of #TrophiChange was completed a few weeks ago. Here's a thread of what I was doing.
#ornithology #SciComm #waders #shorebirds #fieldwork

I am interested in linking #whimbrel chick growth to their food resources. To do that, I started in May by finding as many nests as possible. More nests = more chicks. This season that meant 110 nests.
#ornithology #TrophiChange #waders #shorebirds #fieldwork

But nests of several other species were found and surveyed too, to record laying dates and hatching success, as part of our centre's long term monitoring of breeding #waders in #Iceland.
Here's a golden plover nest, that successfully hatched. #TrophiChange #fieldwork

Back to whimbrels.
It's important to know the exact age of chicks for growth analysis. Hence, I marked most of them with a metal ring within hours of hatching (age 0). How did I predict the hatching date?
#TrophiChange #ornithology #waders #shorebirds #fieldwork

Due to embryo development, the density of the egg changes. By floating it in water, it's possible to estimate the incubation stage and have a good idea of how many more days until hatching.
#TrophiChange #ornithology #waders #shorebirds #fieldwork

To help targeting the chicks later on, it's important to identify the parents. Hence, adults are caught on the nest, measured and marked with an unique combination of colour rings.
This is me doing it. Using the car as a hide helps a lot.
#TrophiChange #fieldwork #ornithology

After chicks hatch, they were searched for and measured every 3 days (not as easy as it may sound, and sometimes this interval was larger). At an older age, when their legs were long enough, each was also fitted with a combination of colour rings.
#TrophiChange #ornithology

During handling, sometimes chicks poop and #poo samples were collected. These will be inspected under the microscope to identify what they consume.
#TrophiChange #ornithology #waders #shorebirds

The chicks grow quite fast, and in about 3.5 weeks they take their first flights and are not caught again.
#TrophiChange #ornithology #waders #shorebirds

In parallel to chick growth and diet data, data on the food resources was collected too. Crawling invertebrates were sampled with pitfall traps, which are emptied every 3 days. Not always in as good weather as in this video, though.
#TrophiChange #ornithology #SciComm

For flying invertebrates, window traps were used. And were emptied at the same time as the pitfalls.
#TrophiChange #fieldwork #ornithology #waders #shorebirds #SciComm

But I'm am particularly interested in the role of crowberries, so I recorded the fruit maturation phenology by determining the proportion of ripe fruits each visit, in quadrats protected from the birds (as they tend to find ripe fruits faster than me!).
#TrophiChange

I also measured fruits every 3 days, and sampled several quadrats for fruit abundance. With the estimative crowberry cover and a mass ~ size relationship of the fruit, it is then possible to calculate how much fruit biomass is available for the chicks.
#TrophiChange

To get even more detail about the habitat, this summer @MiguelVillosPe and @Thaisafb1 joined with an #ebee. This shall allow mapping exact crowberry cover, and link habitat features to nest locations and success.
#TrophiChange #ornithology #remotesensing #fieldwork @DigGeoUef

Until now, the focus was on the period from hatching to fledging. But what do the chicks do after they become independent? Some where tagged with @HQXSCN devices, and have been providing answers.
#TrophiChange #ornithology #waders #shorebirds

I'll share what habitats they use during the upcoming @WaderStudy conference. For now, here's a simple animation of the movements of 6 juveniles before leaving #Iceland.
#TrophiChange

What route do they take during migration, you ask? Is it the same as the adults, as shown in this @AvianBiology paper?
doi.org/10.1111/jav.01…
#TrophiChange #ornithology #waders #shorebirds

Yes! Like adults they fly nonstop to West Africa! I should mention that they are unlikely to join groups of experienced adults. Adults tend to depart 2-3 weeks earlier.
#TrophiChange #ornithology

These are impressive flights, which certainly require a good amount of fuel. What do they eat to get that fuel? I'm trying to investigate it by using #poo and blood samples too (via SIA).
#TrophiChange #ornithology

But in this case, from older juveniles, caught with mistnets.
This isn't easy in a landscape where places to overnight are abundant and the night is short. But persistence pays off and we got some birds. #TrophiChange #fieldwork

Despite the difficulties and short dark hours in August, the nights can be lovely with great views of Northern lights! #fieldwork

Although I do most of the fieldwork on my own (not complaining here!), I must acknowledge those who join me to help. Particularly @TriinKaasiku during growth rates and tagging work, and @Luscinia_joshua, @boddiholly and @TomasGretar during mistnetting.
#TrophiChange

Lastly, none of this would be possible without @RannisIceland funds.
Having a pleasant research environment with great colleagues is also very important!
#TrophiChange