Bird Migration Patterns

It’s that time of year again when I realise that the Yellow-billed Kites have gone off on their holiday up north and I have not recorded their date of departure. One is aware that they have gone but cannot remember when you last saw one; they are such an integral part of any local journey during the summer months, but it is so hard to pinpoint their actual going away. How much easier to note the first sighting in spring when they return to get their nests in order and begin the task of rearing a young family.

I have just spent four glorious days at the Cavern, this time as a guest – what a treat! It’s hard to imagine a more luxurious way to spend time with ones family, no shopping, no cooking, three fantastic meals a day – the weather was perfect too. The berg is a great place to study migration as all three different migration patterns can be seen there. Migration is always a two-way journey; from A to B and then back again from B to A, again and again, year after year. Up in the berg examples of Palaearctic, tropical and altitudinal migration occur.

The Palaearctic migrants have already left to rush back to their various northern breeding grounds; it is important not to be too late and miss the good nesting sites and meeting up with your mate of last year. The Barn Swallow (previously called the European Swallow) is probably the best-known example of this type of migration. They come here from their breeding grounds in Europe and Asia to escape the harsh winter and have a bit of a holiday in our summer months. Other examples are Amur Falcon, Spotted Flycatcher and Willow Warbler.

The tropical migrants, sometimes referred to as breeding migrants, have a different strategy and they breed here in our spring and summer and then head up to the tropics where they spend a couple of months before returning here to breed again. For these birds there is no rush to go; while there is sufficient food and good weather here they will remain, only going when times get hard and the winter chills set in. The Greater Striped Swallows and White-rumped Swifts are both tropical, breeding migrants and they were still whizzing about and obviously finding enough food. I saw a Paradise Flycatcher the other day but they will also be setting off for the tropics any day now.

Then there are the altitudinal migrants, those that breed at the top of the berg and then move downhill when it gets too cold and nasty up there. For the months of summer it is well worth being at the top of the berg, and there are more than a few species that make this journey. The food supply is great but soon dwindles as the cold sets in and so the push to get downhill becomes insistent. The Fairy Flycatcher is my all-time favourite n this group.

 – by Sally Johnson

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