Each spring, millions of fieldfares (Turdus pilaris) migrate to Germany to breed after spending the winter months in Southern France and Italy. In Northern Bavaria, the birds can be seen from late March and are presently busy raising their first brood. A couple of them built a conspicuous nest up on a leafless tree across from my apartment block. I had the chance to observe the five chicks fledge, an experience I find worth documenting here due to some peculiar circumstances.
Fledging is a decisive moment in the life of a bird, one without a second chance because once out the young never return to the nest. It is a bold leap into a ruthless unknown and many chicks don’t make it past their first night out. Like blackbirds, fieldfare chicks are unable to fly for a few days after fledging and must hide on the ground or small bushes to survive; the parents bring them food and warn them of danger by distinctive alarm calls. This is the period with the highest mortality rate for the babies, especially early in the season when the vegetation is still leafless.
As the fieldfare nestlings grew in size, the cup nest looked more cramped. The chicks became increasingly restless and fledging soon became a matter of urgency. Two fledged last Friday, one on Saturday and the two remaining ones on Monday. The female likely started incubating the eggs before all were laid, causing some to hatch earlier, develop faster and therefore leave the nest at different times. Both Friday chicks died but the three others lived until now. Impressively, the Saturday chick could already fly on Tuesday (yesterday).
Chick #1. Flapping its little wings, the first nestling jumped off and landed on a small grassy patch below the tree. Moments later, it hopped its way across the pedestrian path where one parent came to feed it, and before long it had reached the largest meadow.
Thanks to a great camouflage plumage, the young easily vanished among the shrubs, but quickly came out again to explore its new environment, skillfully hopping around. At last, it found a good branch to grip on and undertook a full preening session before having a little snooze.
Although this first chick looked perfectly healthy, I found its inanimated body on the concrete path the next morning. The cause of death might be internal because there was no sign of external injury or attack on the body. Weather is an unlikely cause since temperatures were mild that night.
Chick #2. I was still observing the first chick when loud distress calls from the parents drew my attention. A second chick had fledged and landed on the same grassy spot, but for some reason it wouldn’t come out to the path like its sibling. I decided to have a closer look but before I could sight the chick both parents aggressively flew above my head in great tumult. Then came an avalanche of mud and faeces bombs pelted at me by the protective adults, a defensive practice common to this bird species. Something was wrong with the chick and the parents knew it all too well.
The baby bird could not use its legs properly which caused it to loose balance and fall on its chest and belly. Once in this position, it couldn’t get back on its feet on its own. Rather than hopping, it crawled on the ground using its wings, dragging both its legs behind. The sight was awful and I wished it was a temporary numbness. When it became clear that it wasn’t, I picked up the helpless bird and brought it home hoping to find a solution.
The situation was severe. The crippled bird hardly had command over its feet and leg motion. Legs and claws seemed lifeless and moved quite like rubber band. The ankle joint (see bird leg skeleton image below) was so loose that the lower part of the leg, especially the right one, could bend backward and rotate around it in nearly all directions. The claws had no strength to grip on anything, were oddly curled up and the back one was held forward, together with the front ones.
Due to these various defects, the chick had no balance and fell forward at the first hop attempt. As a result, it could not display normal bird behavior, i.e. preen its feathers―the first thing fledglings do after abandoning the nest―sleep with its head turned on its back and stretch its limbs. However, the chick was seemingly not in pain, at least not physically. It could perfectly use its wings and showed no other sign of illness.
The most alike problem I found searching online is splay or spraddle legs, a condition commonly found in captive-bred birds whose legs spread on the side instead of keeping under them. This results from a bad position in the nest and can be fixed well as long as the chick has sufficient growth time ahead. A calcium/vitamin D3 deficiency can also be the cause. When asked, the Vogelklas KarelSchot (Twitter: @vogelklas), a bird rescue center from Rotterdam, suggested a possible growth disorder that could be irreversible.
Any other suggestion (or confirmation) about the cause is greatly welcome.
Regrettably, the whole thing happened on a weekend, so vets were closed, and there are no rescue center in my area.
I tried fixing up the bird using adhesive tape and rubber band to prevent abnormal movement of feet and legs. Taping claws flat like a duck foot and then both feet together (below the ankle, see photos below) gave the chick some balance. Additionally, a hard piece had to be secured between the legs to keep them constantly apart and parallel.
This all worked quite well but wasn’t enough. On the second day, I added a rubber band to each leg. I secured one end above the ankle and tied the other end to the middle front claw to support the legs and forbid any backward bend (I do not have a picture of this). Despite frequent falls, the chick could finally hop like a bird.
Sadly, the chick refused to feed itself from the begining. It did consume a couple of earth worms, banana and cat food, but in such small quantities that it progressively weakened to a point of no-return. Force-feeding failed, probably because I started it too late. The chick died on Sunday afternoon.
Chick #3, 4, 5. Here are some photos of the three chicks that survived to this day. The Saturday chick (first two photographs) is the one that could already fly four days after fledgling. Today, I was unable to find any chick, neither dead or alive, in the small green corner where they sheltered, so I assume they have now moved to new quarters.
Location: Bayreuth, Germany
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