I left my earlier article asking what of the Yellow-legged gulls that had alerted me to the presence of migrating vultures over Gibraltar? Yellow-legged Gulls Larus michahellis breed on the Rock of Gibraltar and the late spring arrival of Griffon Vultures Gyps fulvus coincides with the time that the gulls have chicks on their nests. Gulls are aggressive within the defence of their younger and so they don’t like massive raptors getting shut. Griffons are about as massive as migrating raptors come so they’re the topic of particular consideration.
That is the final hurdle within the arduous journey of the Griffons that left West Africa and crossed the Sahara Desert. Having made it throughout the desert, they then travelled northwards in direction of the Strait of Gibraltar. These massive hovering birds keep away from lengthy sea crossings however even the 14 km of Strait of Gibraltar might be demanding. In contemporary westerly winds they get displaced eastwards in direction of the Rock, including an additional 7 km to the crossing. They arrive exhausted, solely to be greeted by flocks of offended gulls.
The gulls mob the vultures relentlessly and sometimes drive them into the ocean. The fortunate ones are rescued and rehabilitated at a unit run by the Gibraltar Ornithological and Pure Historical past Society (GONHS) however many others by no means make it.
Griffons are scavengers. They pose no menace to the gulls or their chicks. So why assault them? My hunch is that the gulls merely reply to the raptor form. The bigger the form, the extra intense the response. That’s how they understand menace. What which means is that the gulls are making a mistake every time they cost at a Griffon. They waste vitality and get nothing in return. Or do they? It’s potential that gulls attacking the vultures are measuring themselves in opposition to different gulls and dealing themselves up a pecking order. Gull mobbing might have a standing message between gulls.
Individuals usually describe the horrible gulls that assault the poor vultures. The condemnation of the gulls can get fairly bitter. But, all of the gulls are doing is defending their very own. If there are too many gulls, it’s largely our fault for offering a lot meals for them. I’ve been following the native gulls with GPS tags and so they spend most of their time in garbage ideas in Spain and Morocco. However why ought to we fashion the gull as enemy and the vulture as good friend?
The Griffons meet a fair worse opponent than the gulls once they arrive at Gibraltar. Peregrine Falcons Falco peregrinus additionally lie in wait and defend their very own younger, simply because the gulls do. They, too, will drive Griffons into the ocean and kill them. However, to us, Peregrines are the signal of the Aristocracy, agility and energy, so we by no means sentence them in the identical method that we do the gulls. These are subjective and pervasive attitudes that appear to drive quite a lot of nature conservation. We save pandas and tigers, as we must always, however we don’t give as a lot thought to the creepy crawlies and different less-attractive creatures that additionally want our assist.
