House martins, like their close relative the swallow, return each spring to their familiar mud nests, typically built onto our own homes and offices. Like the swallow, their return each year cheers us up as it reminds us that summer is coming. It is, therefore, somewhat surprising then that, for a bird that is so familiar to us, we know virtually nothing about what happens to house martins after they leave Jersey.

Recoveries of ringed birds from across France and on into North Africa have revealed a migration route south but we have no idea what happens to these birds once they cross the Sahara. House martins are rarely seen in Africa during our winter. There has only been one record of a ringed house martin from south of the Sahara, despite the many thousands of individuals to be fitted with rings in Britain each year (see tracking house martins).

It has been suggested that they remain on the wing and feed above the canopy of the equatorial rainforest, out of sight of human eyes.

However, what we do know is that house martin population in the UK may have declined by 15% over the last decade and may have fallen by as much as two-thirds longer term. In Jersey the house martin was (in 2011) Amber listed as it has shown a moderate breeding population decline (see report here). Since 2011 numbers have continued to decline alarmingly suggesting that it might be Red listed (severe decline in the Jersey breeding population size, of more than 50% over 20 years) when the list is next revised.

It is not clear how many house martins there are in Jersey as it has been difficult to survey them. What we can do is watch closely their colonies and see how they are faring each year and from year to year. If you have a colony on your house or other buildings and would like to record the birds please get in touch with Birds On The Edge by e-mail birdsote@gmail.com The BTO will be carrying testing survey techniques this year before starting a wider survey of house martins in the British Isles in 2015. We will feed Jersey’s results from this year into the national survey.

House martins and their nests are fully protected in Jersey. Please download guidelines here.

From BTO

Climate change is having dramatic effects on many of our species, and not always in obvious ways. A new study demonstrates that climate change disrupts natural relationships between species. Part II of The Intergovernmental Panel on Climate Change (IPCC) fifth assessment report, published at the end of March, reported that climate change is altering species’ distributions and populations with high confidence. However, what is less clear is how and why. Latest research led by the British Trust for Ornithology (BTO) shows that the main driver of change might actually occur through altered interactions between species, rather than direct responses to climate.

Each species shares an ecosystem with other species, some of which it might eat, and others that might eat it or compete with it. Scientists from the BTO and other partners of the Cambridge Conservation Initiative (CCI) found it was the effects of climatic changes upon the populations or activity of these other species which were responsible for many of the impacts observed, as they cascade through the food chain. For example, Arctic fox populations have been affected by declining lemming populations linked to changes in snow cover, and also by expanding red fox populations. Hungry Arctic foxes may look to other prey such as breeding wildfowl like brent goose and waders like sanderling  (they already feed on these birds during ‘lemming years’ – in Jersey we don’t see any young geese at all some years). In the UK, upland birds such as the golden plover are affected by increasing summer temperatures, which causes problems for their cranefly prey. These disruptions particularly affect predatory species, and appear to have worsened with climate change.

Dr James Pearce-Higgins of the BTO said, “Although it might be assumed that most species are responding directly to climatic changes, either as individuals move to keep within their favoured climate zone, or through survival and reproductive rates linked closely to these climatic variables, this does not account for the majority of impacts. Instead, the main impacts of climate change occur through altered interactions between species within an ecosystem.”

Importantly, as much conservation action is already about managing species’ populations, such as controlling invasive species or reducing predation risk, we already have the conservation tools in place to reduce the impacts of climate change on species. This understanding, therefore, provides hope that we can help the most vulnerable species adapt to climate change, providing the magnitude of climate change is not too great, and that conservation activity is sufficiently funded. For example, in the UK uplands, we can restore degraded peatland habitats to boost invertebrate cranefly populations, and increase their resilience to climate change. Whilst this work also helps identify the types of species’ most vulnerable to future climate change impacts, there remains a lack of information from the tropics, where most species’ occur, and where increased monitoring and research is essential.

“This study highlights a need to consider the often complex ecological relationships between species when assessing the impacts of climate change on wildlife.” says Jamie Carr of the International Union for Conservation of Nature, a co-author on the study. “Most research to date has focused on the direct impacts of changing conditions, which may mean that important emerging threats are being overlooked.”

The report can be seen here

From Ramsey Island and Grassholm

This month saw the start of an innovative project in local waters aimed at trying to lure puffins back to Ramsey one of the Pembrokeshire islands and an RSPB reserve. Puffins used to breed on Ramsey in the 1800’s but with the arrival of rats through shipwrecks their days as a breeding species on the island were numbered. Rats are, as we have seen on other islands (see here and here for other local examples), voracious predators and when they find their way onto seabird islands their impact is devastating. Millions of years of evolution have seen some species of seabird adapt to breed in burrows underground. This allows them to avoid avian predators such as gulls but when you suddenly introduce an alien mammalian predator to which they have no defence the impact is catastrophic.

Work 14 years ago by RSPB and Wildlife Management International meant that the introduced rats were finally eradicated. The response of Manx shearwaters has been impressive with an increase from 850 pairs in 1999 to 3,835 pairs in 2012. Storm petrels were recorded breeding for the first time in 2008 but puffins have not made it back yet

Four years ago, decoy puffins were put out on Ramsey’s cliff tops in the hope that they might attract puffins regularly seen at sea around the Island (there is colony nearby at Skomer Island) but with no success. However, seeing the responses of puffins at Copeland Island where sound was added a couple of years ago it was decided to try this approach on Ramsey. Nigel Butcher, ace technician in the Conservation Science Department at the RSPB made the sound system which plays the call of a puffin on a repeat loop from a loudspeaker (very loudly!). German technology then completed the outfit when Michael Hoffman, one of Ramsey Island’s regular and very talented volunteers made a sturdy frame on which to securely site the device plus a solar panel to keep the battery topped up.

The decoys accompanying the sound system were made by Ed Tycer. It is hoped these will act as an added attraction if birds make landfall.

The system was trialled last year for a short, four-week period, with some success whilst dealing with early teething problems. Birds were recorded making landfall on low tide rocks below the speaker and on one memorable occasion eight birds landed on the cliff tops among the decoys. With the device out for a full season this year it is hoped the project can build on this success and see puffins return to their rightful place on the Ramsey Island breeding bird list.

Could a project like this work in the Channel Islands? Well, yes, in theory it would be well worth trying. However, where is there suitable puffin-friendly ground that has no rats? That is pretty scarce and the best current puffin site, Burhou, probably already has space for more puffins anyway. But, with tiny colonies away from Burhou only barely surviving, could birds be lured to safer spots? That might well be worth trying – but first, get rid of those pesky rats!

Birds On The Edge is grateful to Greg Morgan for help in producing this report. You can follow the Ramsey puffin story at the Island’s blog and even on Twitter @RSPBRamsey