Some years ago the NISG posed the
question – “Where do our Swift go for the 265 days or so that they are not with
us”? Here below is largely the long awaited answer.
Northern Ireland Swifts- Apus apus -
Migration Journey to and from Africa. What we know in 2022.
The Journey to Africa
Unlike we
humans, who may decide to book a holiday somewhere and then fly there direct to
stay in a hotel for 2 weeks, 2 months or longer Northern Ireland swifts make
their way to Africa in a very different way!
They do not just fly straight to Mozambique, which we now know,
is their ultimate destination.
Rather
they migrate there in stages, rapidly moving through some areas, stopping in
others briefly, or indeed staying in favoured areas for weeks or months at a
time, before moving on.
By the
end of July each year all over Northern Ireland, many of the young Swifts which
only hatched earlier in the year in June are already fledged and heading towards
Africa. Around the 12th of July swift breeding activity throughout
the country is at its peak, but within the next 3 weeks,
it will start to drop off significantly
as more and more swifts, both adults and young of
various ages, start their migration.
Each year
newly fledged Northern Ireland swifts leave their nestsites in late July and
into early August and immediately head off on migration, totally independent
from their parents. They have a
built in programme, in the form of an internalised sun and star map, which tells
them where to go and how to get there.
Amazing!
Meanwhile
the parent birds, once freed of their fledgling feeding responsibilities,
general stay on around the various nesting sites and colonies for periods
ranging from a few days to a few weeks in some cases, before they head off on
their own long journey to Africa.
Figure 1- Swifts at the Crescent Arts
Centre in Belfast on a July Evening – photo by Dr. Liam McCaughey
-
“The swifts last evening flights around
the Crescent Arts centre colony in Belfast before the long flight to Africa”.
Because it takes swifts around 4
years to reach breeding age, immature non -breeding swifts of various ages, the
one, two and tree year old birds, generally leave on migration before the
breeders of that particular year.
As we
move into early August, the spectacular high speed flights of Swifts around the
nestsites and colonies, which are so characteristic of fine weather in mid to
late July, become less and less. By the
second week of August colonies and nestsites fall completely silent as all the
swifts leave. This departure coincides with the last real warm sunny days of
July and early August. It will be a long, long, time before these marvellous
birds will grace the skies over Northern Ireland again.
In all the swifts are only with us here
for around 100 days and away on migration for the other 265 days!
Figure 2- Example track of Swift
Migration to and from Northern Ireland to Mozambique showing route taken, the
main stopping points and favoured feeding areas.
black line
– the journey south to Africa
Red line
– the journey home to Northern Ireland
Whatever
their ages or experience the migrating Crescent swifts head down the east coast
of Ireland and moving fairly quickly, generally reach Wales by the next day.
From there they cross to England and travel on southwards, via France to Spain
and Portugal, arriving there generally a week after leaving Northern Ireland.
The arrival times and length of stay here in the Iberian Peninsula are
dependent on weather movements and patterns over Europe, which influences both
flying conditions and insect food availability.
The birds
then cross the Mediterranean Sea, a week to two weeks after leaving Northern
Ireland and enter the African continent via Morocco.
From here, feeding when they need to and
constantly on the wing, they migrate down through the Western Sahara and
Mauritania, moving fairly swiftly and spending their nights sleeping on the
wing! Sleeping on the wing? Yes.
Almost unbelievable, but true!
From here
they head down across Senegal and the Gambia swinging westwards through Mali,
Burkina Faso, Benin and into Nigeria. Moving on they travel through Cameroon,
some of the earlier migrating birds arriving there around the end of the second
week in August.
From here
they travel quite quickly through the Central African Republic and on to the
Democratic Republic of the Congo (DRC).
The have already travelled a long way in a relatively short time, (2 – 3
weeks) but in many respects their journey and wanderings are just beginning!
The
Democratic Republic of the Congo is a vast country, slightly bigger
than the combined areas of Spain,
France, Germany, Sweden, and Norway. That’s Big!
Maps generally show countries out of scale with the true size of the
African Continent. The following map Fig. 3 shows just how far the swifts
travel, when you look at the size of China and the USA superimposed on Africa!
Taking advantage of the tropical
climate and the rich feeding on aerial insects, they stay in this general area,
although ranging widely, for about a month, to 6 week s.
Their wanderings around the DRC can sometimes see them move into North
East Angola by late September.
Wherever they roam in the DRC, the
first few days of November see them heading east and south again through Zambia.
From there they pass through Zimbabwe or along the western edge of Botswana and
by Mid-November they will usually have reached Malawi, where there is a vast
lake of the same name. It is the third largest and second deepest lake in
Africa! Here, they again roam widely feeding on the rich supply of
airborne insects. From here they move
into Central and Northern Mozambique drifting southwards towards the southern
reaches of Mozambique and its capital city Maputo, a port on the Indian Ocean.
Maputo is around 8000 miles from
Belfast, as measured by the most direct route down Africa through and across the
Sahara desert, but remember the swifts don’t take this direct route- see Figure
1 for details. Rather they take a more meandering route and staying airborne day
and night they cover more like 12,500 miles before they reach Maputo! Truly
remarkable!
By Christmas Day some of our Northern
Ireland swifts can have drifted into the skies above Limpopo, a northern
province of The Republic of South Africa. It is named after the Limpopo River
the second biggest in Africa, its name deriving from the local Sepedi native
word for ‘strong gushing waterfalls’.
It’s amazing to think that the same
birds we see speeding around nest sites in Northern Ireland on the 12th
of July can be flying over these breath-taking waterfalls in Limpopo on
Christmas Day!
Limpopo is in The Republic of South
Africa, but borders Botswana, Zimbabwe
and Mozambique and includes areas of the Kruger National Park, which itself is
the size of a third of Ireland!
Christmas passes and by New Year’s Day,
when we are maybe shivering in the cold and wet of our northern winter, Northern
Irelands swifts are likely to be flying around the skies above the Kruger Nation
Park in the Republic of South Africa, with Elephant, Rhino, Giraffe, Hippos,
Buffalo, Zebra, lions and wildebeest to name but a few, looking up at them!
Amazing!
Figure 4 – Greetings from the Northern Ireland Swifts on Tour
–
“Having
a wonderful time here in the Kruger – Wishing you were here”!
“Happy New Year and we hope to see you
all next May! “-
The Swifts.
The return Journey from Africa to
Northern Ireland
It is at this stage of the early New Year that our
swifts start to head for home. The
area they are now in is rich in wildlife and contains many Nature Reserves,
National Parks, Private Game reserves and other richly bio- diverse regions.
Close to Kruger in the Republic of South Africa for example are the Bahani
National Park in Mozambique and the Gonerazhou National park in Zimbabwe, all
packed together in this region of Africa.
Who knows what instincts or factors
work on the brains of the Northern Ireland
swifts to make them turn northwards towards home, but by around the 4th
January they are already heading north through Southern Mozambique. By the end
of the second week of January and towards the third week they reach Lake Malawi
again on the borders of Mozambique, Malawi and Tanzania. They then head up
through eastern Zambia towards Lake Tanganyika another vast African lake, the
longest and second deepest in the world!
This lake is shared between Tanzania,
The Democratic Republic of the Congo (DRC), Burundi and Zambia.
Moving on, the birds enter into the southern regions of the DRC flying
over and feeding in the Upemba National Park in the southeast of the country by
the second week of February. Where
exactly they wander and how long they stay in any particular area, in any
particular year, varies according to local weather conditions and food
availability.
The National Park covers a vast area of
lakes such as Lake Upemba. Huge
expanses of marshes also occur here and this combination of habitats contributes
greatly to the overall rich biodiversity of the Congo River Basin.
Unfortunately, in recent years the National Park, once Africa’s biggest, has
almost halved in area and has come under considerable attack from poachers and
local militias. A worrying development for the migrating swifts?
They continue to roam in the southern
areas of the DRC until around Mid-march feeding opportunistically and taking
advantage of local insect population, resulting from the rich habits and
prevailing weather systems. Around
this time they move into the Republic of Congo (ROC ) from the DRC.
Note that there are 2 Congos-the DRC and ROC!
By
St Patrick’s Day, as Northern Ireland looks towards spring, the Swifts are
generally heading across Cameroon,
arriving in Nigeria by early April.
Not long to go now!
From Nigeria the migrating swifts move
through Benin, Togo, Ghana, and the Ivory Coast and into Liberia reaching there
around the third week of April, as Northern Ireland wakes to its warming
sunshine and first flushes of Spring Blossom. In Liberia the swifts may stay for
up to about 10 days in a stopover to fatten up and prepare for the final leg of
their long journey.
The urge to move north is now very
strong as the established breeders are bursting with hormones and are keen to
start nesting, as time is short in our northern summers to complete their
breeding cycle.
Leaving Liberia in the last days of
April the birds take a much more direct route home than they do on the outward
journey, flying northwards over Guinea and Mali through Mauritania, or Algeria,
and on to Morocco. From there they
fly directly through the Iberian Peninsula up the coast of France and over the
Bay of Biscay and the Irish Sea to Belfast and all over Northern Ireland.
This last leg of the long journey can
be completed in around 10 to 12 days or less depending on what weather systems
prevail over south and North West Europe, at any given time in any year. Bad
weather can sometimes delay some birds and they generally avoid low pressure
systems and heavy rain. However, in
either the last week in April, or during the first week of May the vanguard of
Northern Irelands adult breeding swifts arrive.
No wonder that they scream with delight
as they take their first frantic flights around the beautiful old buildings in
our towns and cities, hopefully on a sunny day.
An epic journey indeed since they left Northern Ireland the previous
July!
They have been flying continuously day
and night and sleeping on the wing, while they meander through at least 40
countries in a journey there and back of around 25000 miles!
What superb travellers!
-As the established breeding birds hurtle into their nestsites at dusk on
their first night back in Northern Ireland it will have been, for most of them,
265 days since they last landed and felt solid ground beneath their tiny feet!
WELCOME HOME SWIFTS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Extract from the poem Swifts 1976 by
Ted Hughes Poet laureate -
“Look!
They’re back! Look! ---
They’ve made it again, Which means the globe’s still working,
The Creation’s
Still waking refreshed, our summer’s Still all to come —“
Which proves the globes still working
………….
Let’s hope this continues for many
years to come. Save our Swifts!