Today's blog is from David Ramsey, a member of the Mid-Pembrokeshire Local group. He talks to WTSWW about Swifts in Milford Haven.
The Swift was once a common breeding summer visitor in Wales, but has sadly declined by over 50% in the last 25 years. The causes of this are multiple and now fairly clear, loss of nest places as buildings are renovated, insulated, restored or demolished and replaced with buildings without the eaves or gable gaps the birds need to nest within, and a massive increase in the use of agricultural insecticides which is “taking out” the flying insect food that Swifts depend on.
Added to that the increasing frequency of extreme weather events in Europe which has been proved to have caused mass deaths of Swifts on migration, and there is now a cloud of suspicion lying over anti-locust spraying in Africa. Insect eating birds are in many cases about the same size as a mature locust, and so the same dose of insecticide may well kill them, and they will eat dying insects that have been sprayed, and absorb fatal dose of insecticide that way too.
Swifts spend the winter months in Africa and migrate here in the spring to breed and are faithful to their nesting site year after year. Preferring a cavity in building or occasionally cliff cave. The Swift has a life span of about 10 years and spends most of this time on the wing feeding, sleeping and mating. This is quite similar to our ocean-going deep-sea birds such as Petrels and Shearwaters.
So, with all these adverse events affecting them we have to try and help Swifts as best as we can, and that means creating new nest sites for them, and campaigning against the excessive and unjustified use of insecticides, for example in and around our towns as well as out in the fields.
Why Milford Haven?
Over many years I have observed the summer Swift population over Milford Haven, from the first screaming fast sorties in late April with few birds, (usually about 3-4 individuals). These birds are very actively hunting for nest sites, (every year checking roof soffits for cavities).
Followed by a few days of silence and then another wave of arrivals, loose groups of up to 15 birds feeding high above the town only giving their presence away by the magical calling on warm dry summer evenings. It really lets you know without exception that summer is here, and that we can expect, or rather, wish that it will be a beautiful and relaxing time.
It is difficult to come to conclusions with just observation and no evidence of nesting birds. For a start, Swifts are very elusive and quiet about their nesting, for instance, there are no give a ways, like mess, noise or droppings, and gone in a flash, silence! To add to this difficulty the nest will be over 5 meters from the ground (if you look up while walking through Milford Haven, you might walk into a lamp post).
Another problem is building renovation, roof and soffit are good nest sites for swifts and these are obviously necessary repairs to ageing buildings. This reduces the available nesting sites for swifts and increases the competition. One worrying population trend is the lack of a trend at all. This may seem strange, but the number of individual birds returning each year has remained low, but consistent for many years.
In my opinion, we have maintained a carrying capacity of about the same for many years. Although this consistency might seem encouraging, it is also worryingly low, and the small population of Swifts could crash completely.
The way to increase the population of Swifts in Milford Haven is to provide nest sites for them. We have confirmed that small numbers are active in the town and a second wave of birds arrive shortly after this. However, by mid-July the number of individual Swifts reported over Milford Haven town centre was about 30 birds in one group alone.
There is only one brood per year with an average of 1.5 chicks. They take a long time to reach the state when they can fly, an average 42 days. Broods of 3 chicks are very rare, and while Swifts may lay again if the first brood is lost, they rarely if ever try a second brood.
By early August the swifts begin their migration south (It is never a last minute dash like the swallow or martins which have up to 3 broods per year and sometimes start migration very late). More of an amble, pausing in good feeding locations to allow the young birds to develop the skills they need to catch their own flying insect prey.
The Swift is an urban bird that seems to do well at coastal sites too. The Milford Haven location is an ideal setting for this aerial master. It has old buildings well suited as nest sites and a green urban setting, no use of insecticide and the proximity to the Milford Haven waterway provides an excellent habitat for invertebrate food.
There is a proven link between encouraging biodiversity in towns and cities and better human wellbeing. For instance, the Bristol Swift Project has shown that people can become more occupied and connected to nature, thus giving a sense of being part of nature and a culture has developed there. Citizens welcome and look forward to the return of the Swifts and celebrate it when they arrive.
How do we increase the population of Swifts?
Begin by making, and fitting Swift Nest Boxes (SNB) in Milford Haven. This project will cost very little money and the swifts, social and community benefits over the coming years will be great. (Just time and some expertise are all that is required.
(1) Now is the time to act for Swifts in your location.
(2) The location must be sound, and not in need of restoration in the near future. A well-made external Swift box should last at least 10 years if made from 12mm marine ply with glued and pinned joints.
(3) Directly under eves or soffit at a minimum of 5 Meters from the ground. Corner box at eves under soffit. Make sure it is located away from potential perches for other bird species. Make sure you don’t leave gaps for other lodgers to nest. Unless you are extremely handy on a ladder, do not attempt to fix it yourself. Do not put yourself in danger.
(4) Swifts often nest in colonies so 2-3 boxes or a gallery style box.
(5) Boxes should be sited in shade for protection from the hot summer sun. North, West and East facing locations are usually suitable. Avoid sites that get the prevailing rain and / or cold winds, as Swifts suffer from damp and cold as much if not more than from heat.
(6) Research on Swift behaviour, and look at the resource material included at the foot of page.
(7) To increase your chances of success play Swift call CD, or other audio setup.
(8) All resources and necessary knowledge and myriad of different box styles and instruction are available through Swift Conservation’s excellent website.
Information from this blog can be found here.
David gives special thanks to Anthony Rogers, Pembrokeshire Nature Partnership (PNP) Conservation Team.Edward Mayer, Swift Conservation organisation.