Gliding and Nature

One of the most satisfying things about free flying is how it allows you to become involved with nature at many levels.

First there is your personal interaction with the weather elements whose greater understanding will keep you safer and improve your flying.

Secondly, observation of plants and animals plays a very important part in the enjoyment of paragliding for me. There is no other aviation sport where you are so involved at such an intimate level with both the air and other living things around you. Most launches are at remote mountain locations, so just your arrival at the site puts you in a fantastic natural environment. Once in the air, you can get close to other flying creatures and fly closer and slower to the terrain than in any other form of flying which gives us a unique viewpoint. Importantly, our observation of ground vegetation and flying animals can give us vital clues as to what is going on in the air and which will help our cross country route planning, as well as adding enjoyment to the flight.

Birds you may fly with

Flying with vultures

These large birds make cross country flights to search for carrion. Because of their bulk, they will only normally be seen flying with the onset of soarable conditions. Their sink rate is similar to ours, so if we see vultures climbing it is worth taking off and trying to stay in the air. Of course, their circling diameter is narrower than ours and their manoeuvrability and skill much greater. So, it maybe a struggle for them to stay up and maybe impossible for you.

Photo of vulture

It is generally worth diverting on a glide if you see vultures climbing; however, beware if you see a very large number circling near the ground, as they may just be circling in poor lift to stay near some to some carrion.

If you are circling with a vulture, always watch as it leaves the climb to see the route it takes. Sometimes it moves on a few hundred meters (still within eyesight) and picks up a stronger climb. With large gaggles you will be able to read the multiple cores of the thermal as the birds shift from one area of lift another. They are experts in finding the best gliding line along the lines of lift theorised by many. Even on an evening restitution flight, you can observe how they will often move much further out from the ridge than would expect for the best dynamic lift, yet they usually seem to benefit from the decision.

The mountains above Piedrahita have wide areas of unfenced pastureland, grazed, mostly unattended, by the local Avila breed of cattle. EEC regulations normally call for all livestock dying on farms to be taken away and buried or incinerated. The poor access to these pastures means that this anti-vulture legislation is difficult to carry out. Any livestock dying on an inaccessible part of the mountain is naturally dealt with by the carrion eaters. On the days following these events, we are guaranteed a huge number of vultures in the air near take off. In 2005 we put out 600kg of carrion in the Bees landing area to attract vultures for the filming of a BBC documentary about Vultures. On such days the vultures would roost on the rocks to the right of take off, waiting until conditions to become soarable, before entering the ®dining area® at the landing site.

Griffon Vultures.

Griffon Vulture

Griffon Vulture

The central chain of mountains has the largest populations of Griffon vultures in Europe. On almost every cross country flight you will come across huge birds (wingspan of 95-105cm). Either alone, or at times in large gaggles, they will home in and use a thermal you are in, just as you use them when looking for a climb. Late in the afternoon when the restitution has set in, you may often see them going past take off, coming from the east, flying perhaps to their nesting sites in the Gredos (there are many nesting sites along the take off area at Lastra del Cano. If the conditions are flyable there you are guaranteed to fly with them).

Black Vultures

You'll share a thermal with a Black Vulture much more infrequently than with the common Griffon. They have wingspans of between 250cm to 295cm, and are darker in colour that the Griffons with an unmistakable barn door appearance to their outstretched wings. During 2007 we had regular sightings. There is a pair supposedly nesting near our take off at Lastra del Cano. This now gives us access problems up until August, by which time the young will have left their nest.

Birds of Prey.

Red Kite

Red Kite

There is a huge variety of birds of prey in Castile. There seems to be an abundance of Buzzards and Red and Black kites in the valley, which I always find particularly useful for low saves. Whereas you tend to come across Vultures at mid levels, the Kites will be close to the ground, with a keen eye to ground prey. On the hillside from a few hundred meters above take off, and often at the mid level along the spines you will other midsized raptors, such as the booted eagles which always seem to be hanging out at the house thermal at the Chalets.

Because of their smaller size, I often spot such birds quite by accident when already quite close to them. Moving across to their core is then just a short glide. Vultures I generally spot from a distance, whilst still high and on a transition. Sometimes, by the time you get there the vulture will have moved on or climbed higher making it difficult to find the thermal and the bottom level of the lift may now be well above our arrival height.

Depending upon the time of year you may see pairs of raptors, often making calls to each other as they climb with you in the thermal, or sometimes making stooping dives and acrobatic displays.

In the early 1990s there was a very territorial Golden Eagle who would attack any gliders in his territory which was around the area of Villafranca and up to the pass. You will sometimes be squawked at by birds, taking up position along your glider. I find it interesting that they define such a large territory, often reaching over a thousand metres above the ground.

Swifts, Swallows and Martins

Photo of Swifts mating

These migratory birds come in their thousands to our area each spring and you will regularly find them in the stronger thermal climbs. They are rarely found in large numbers near take off, although there were a pair of Crag Martins nesting in the Bar at take off during 2006 and 2007.

These birds feed on any small creature small enough to be hefted up in to the air by the wind and thermals. They are absolutely the very best thermal markers, and will track around the core always out climbing you and often in groups of up to fifty or more. Their speed relative to us is so fast, and their movements around the core so seemingly erratic, it can feel as if you have been overcome by a swarm of giant bees as they suddenly come through the thermal and climb out above you. It is always best to follow their shifting movements when in a large group. They will be tracking the insects being bought up from below in the most active part of the core.

You may spot a large group and that will help you to find a thermal over a short distance. Usually however, I find that the swifts become apparent once I have already found some lift, and are helpful in homing in on the best part of the thermal.

In the late afternoon you will come across thousands zipping around in the restitution above the town. Viewed from the street, the Swallows often seem to play interesting flights at very low level and often directly towards you, sometimes making almost 180 degree turns right in front of your face.

Storks

Photo of stork and chicks

Any visitor to Piedrahita is struck by the amazing number of stork nests. There are about 15 nests just on the church in the square. They arrive around February time, starting work on repairing existing nests or building new ones. Once the business of chick rearing is done they leave us at the end of July to return to Africa. Their food source are invertebrates and small reptiles and amphibians.

For the parents, the business of finding food and nesting material involves flying to favoured fields nearby. They will rarely go very high, as they are not at this time making large journeys. They will of course use thermals, but are not very selective for strength or quality at this time; anything good enough to take station over their nest or potential foraging site. If I am desperate and low I will fly to a circling stork, but will not usually divert course if I am high.

One of the most amusing times to fly with them is at what I think of as ®flight school®. This is after the young start to make their first flights and often fly in large gaggles around the valley. You know you are involved in a flight school because the participants are mainly a very clean and bright black and white (the adults white plumage is usually a dirtier off white/cream colour). The best time to get involved with a Stork flight school seems to be early in the afternoon, often when we ourselves are starting our XC along the mountain. Essentially they are practicing thermalling. They will climb in their gaggle, and then when they get to a to a certain height they will extend their legs for more parasitic drag (their airbrakes) and commence a dive to loose height with their wings semi swept. Once they loose a few hundred meters in the thermal, they will then start thermalling to gain height again. I?ve observed these training school gaggles only on light wind days. They will often follow our XC route going downwind, but will turn back as a group within about 8kms. Perhaps nearer to migration time, when they have more experience they range further and I have not noticed the turnaround point. Flying along with a stork flight school is one of those special little moments when you think you have glimpsed a wonderful aspect of nature that few in the world can ever experience.

Stork Gaggle on Migration

Stork Gaggle on Migration

One of the most spectacular experiences of flying with soaring birds is to be amongst a gaggle of migratory Storks on route to Africa who travel in groups of many hundreds. On such a day the birds may group in gaggles perhaps coming from further from the north. But what is sure is that they all go together, the gaggle flying being most effective for the long XC route. Normally, the day after flying with such huge gaggles, all the nests in Piedrahita will be empty. Sometimes I have flown with large gaggles and the Storks of Piedrahita are still there the next day. I imagine in this case, I have been with and advance flight school, or perhaps a gaggle coming further from the north and not from our town.

Other airborne creatures

Spiders

Look up at your suspension lines and you will see hundreds of thin gossamer threads. These are of spiderlings ballooning. The young spiders will climb to a high position and let go a spinnaker of web to catch thermal and take them on a ballooning trip to help the geographical spread the species. Your paraglider has acted as an airborne trawler, catching the little balloonists as you glide through that soupy mix of other creatures using the updrafts.

Insects

Flying insects, whose normal interests are much closer to the ground, are often taken up high into the atmosphere. Apart from distributing them around the planet, this offers little for them as individuals, as the cold temperatures aloft will certainly slow them down, if not kill them. Most of the creatures taken up involuntarily will concentrate at the inversion level. Those dark stripes across the sky which you can see from take off are not just dust and grime, but full of life.

During a big task in the 1997 PWC (Open distance to the West), the day coincided with a very large population spurt of ladybirds. On reaching the inversion pilots found their gliders filling with these little red and black insects, which also gave the inversion, from the pilots perspective, a reddish tinge.

Some interesting animals you may see from the air

When skimming the hill on an evening flight you will notice many trails amongst the gorse buses. These maybe cattle trails, but may also be for fox or wild boars. It is quite a delight to follow a fox along a trail, or to see a boar break out of the gorse as you fly by.

Plant life? ... is that important for gliding?

The way that air is heated and thermals formed depends upon how the ground has been warmed by the sun. The amount and type of vegetation cover is very important when determining thermic potential of an area.

You do not need to be a botanist to fly effectively, but a rough understanding of what is down there on the ground can help you in your flying decisions.

With forests the main difference is between evergreen and deciduous trees The bulk of the forest on the lower slopes of our local mountain is the tightly packed deciduous Pyrenean Oak. To the north, on the dry slopes facing south you will find the Spanish evergreen oak, with much more waxy leaves and greater spacing between trees. I think we need to consider the transpiration rate and the insulation effect of the foliage. Also maybe how tightly they are packed. There is a block of Pine trees at the lower level of the forest surrounded by the native Pyrenean Oaks. I think that this often works better as a source early in the day. As a working theory, the waxy leaves of the pine trees probably transpire less than the oaks. Early in the day the cooling effect is perhaps less. Of course, moist air is less dense, so later, when things hot up, the oaks are a better source due to their higher relative humidity. Just a thought!

For sure, later in the day the forests will release their heat later than the bare sections and probably the more sparsely populated Evergreen Oak areas.

When flying over the plains you will sometimes see a change in colour of the grass: perhaps a greener patch in an area of parched gold. This will indicate natural springs or the proximity of a stream or river. On a hot dry summers day this is often a good thermal source. A trick I used in Australia and South Africa is to fly to the dams for climbs. We have few small reservoirs here, but areas of higher humidity along the streams can be a definite help. When over the pass on a blue day with no thermal markers, it is often a good option to follow the river bed of the River Ambles. As well as the extra buoyant humidity, watercourses will be lower, acting as a break from any winds, allowing heated air temperatures to rise higher. Also, you will normally find there is no surface water in the rivers in high summer, but you will be able to plot the course of the river by looking at the tall Popular trees which line the banks of the river. The presence of these trees may also help as a trigger to kick of thermals especially on days with wind.

Most gliding books you read will explain the merits of dark ploughed fields and also how good dry stands of crop are. In the Ambles valley, you will find both, often side by side. I am still unsure which the best to go for is. In such a flat area, I think the superheated ground layer of air may move in large sections over a range of fields without triggering, perhaps triggered by an elevation or interruption in the terrain if there is any wind. With no wind, I would imagine the darker field?s work best, as they will be heated more (with breeze a crop will heat more due to the shelter from the continual fanning of the wind).

Smells

In may and June the gorse on the main ridge comes into flower, starting in the valley and reaching the yellow bloom slowly creeps up the mountainside. At this time your thermals will be very fragrant. All thermals will carry an odour of their source, but this one is particularly powerful and pleasant.

Landing Fields

When it is time to land you must also think about what is in the field. Most of the fields closer to the hill around Piedrahita contain only grass. This however is considered a crop, so in May and June, while still long and uncut, try to avoid trampling too large an area. In the Ambles valley, there are many large cereal crop fields. However, there are plenty of options of fields left in fallow, and by midsummer most are just stubble fields.