I don't know if you have heard many Cuckoos (cuco común) this year, but where I live they have been noticeable by their scarcity. It is a bird whose population has been declining rapidly in the UK and over there it is on the red list for conservation concern - definitely not good news.
However, they have always been fairly common around where I live in Spain and it has been a pleasure to listen to the emblematic calls of Cuckoos every spring.
According to the official Spanish figures, the Cuckoo has shown a moderate population increase in recent years. The Spanish Ornithological Society (SEO/Birdlife) compiles the population data for birds through a variety of national censuses carried out principally by volunteer amateur birders all over the country. This type of volunteer survey, known as 'Citizen Science', is important and the results are being used by national governments and the European Community to monitor climate change, the affects of the Common Agricultural Policy on habitats and changes to biodiversity. This is because birds are an amazing indicator of the health of our natural world because populations can increase, decrease or relocate quickly due to improvements or deterioration in their environment. For example, the South of Spain (Almería and Murcia) is gradually being colonised by an African bird called the Trumpeter Finch and this is widely thought to be due to climate change and the increased desertification that is occurring in these provinces.
However, I have digressed, so I will get back to my theme of Cuckoos. I have participated in SEO censuses every year since 2008, so have been able to consult the data base for 'my patch'. It would appear that the average number of recorded Cuckoos per year was 16 and the number has been fairly consistent up until now. However, this year I have recorded only 2, so I am hoping the figure is only a blip and not something more serious.
As you probably know, Cuckoos are summer visitors and arrive here in April. They only stay for 3 months, which is obviously enough time to find a mate and suitable host nests in which to lay their eggs. They then return to their wintering quarters in central Western Africa, mainly in the Congo rainforest. This lifestyle requires them to make a hazardous journey across the Mediterranean Sea and the Sahara Desert. It is generally thought that environmental conditions in Africa, especially habitat loss and increased desertification of the Sahara, could be important factors in the current poor survival rates of young birds and subsequent diminishing populations. It would be a great pity if we couldn't hear this favourite harbinger of spring in future years.
Our common Cuckoo has a very close relative here in summer and it is a spectacular looking bird called the Greater Spotted Cuckoo (Críalo Europeo). It is a rarity in Northern Europe, but can be seen here in Murcia. It is slightly larger than a Common Cuckoo and is very striking and unmistakable when spotted, as you can see in the photographs. Males and females have similar grey and white plumage, but the juveniles have blackish upperparts and cap and chestnut on the wing feathers. Its flight is a bit like a Magpie and it is a similar size, but with a shorter tail.
Like all Cuckoos, it lays its eggs in somebody else's nest and avoids bringing up the kids. It must save a lot of heartache and trouble! In Spain, they generally look to lay in a Magpie's nest, or if not, the nest of a Carrion Crow. A couple of years ago, I was disturbed by some birds making a hell of a racket near our house. I saw that the local Magpies were being harassed by a Greater Spotted Cuckoo. The sound they make isn't the most attractive song you will ever hear, nor do they 'cuckoo'. Anyway, the Magpies reacted furiously and there ensued a long, noisy chase around the fields as the Magpies ganged up on it and tried to chase it off. A perfectly understandable reaction by the Magpies. However, whilst this was going on, another Greater Spotted Cuckoo suddenly appeared and very quietly went into the Magpie's nest and presumably laid its eggs. I felt privileged to witness the Cuckoos' carefully concocted and well executed plan to distract the Magpies; plenty of teamwork with that couple!
Evidently, the Greater Spotted Cuckoo chick doesn't evict the young of its host, but continues growing up alongside its half brothers and sisters. They normally lay 1-3 eggs which generally hatch before the Magpies', thus giving them an advantage over their new siblings as they will greedily grab most of the food from their foster parents. This sometimes leads to starvation of the weaker Magpie chicks, but not always. So, if you are a fussy or slow eater, don't come back as a Magpie, especially if there is a strange looking half brother or sister sharing your nest!
Finally, a thought about SEO/Birdlife, it is the equivalent of the RSPB (Royal Society for the Protection of Birds) in Spain and has just over 12,300 members. The RSPB has over 1 million members. It is a staggering comparison between the two sister organisations, which brings into focus the relative interest levels in birds and nature between our adopted and native countries (assuming you are British). If you would like to support SEO/Birdlife and their work, why not visit their website www.seo.org (there is a translation option) and become a member. A family membership currently costs 8€ a month.