Birds of southeast Texas in photos

Vultures use Face Flushing Technique for Instant Status Updates

Tech savvy humans who use social media sites to instantly update their ‘statuses’, may be behaving like vultures who use ‘face flushing’ as a visible way of instantly updating their own status when interacting with peers and rivals. Research, published in Ethology, reveals how the ability to rapidly change skin colour is a key form of interaction for vultures, especially for displays of dominance.

The ability to rapidly change skin colour has been well documented in reptiles and fish, which use specialist cells to disperse and concentrate pigments. However, the ability can also be found in some mammals and bird species which exhibit bare skin, such as the vulture.

“Vultures have un-feathered sections of skin on their heads which can become bright red when blood flow is increased, a technique known as flushing,” said Dr Andrew Bamford from Nottingham University. “The advantage in using their bare skin as a signal is that colour changes can occur more rapidly than in feathers or fur, provide up-to-date information on status.”

Dr Bamford and co-authors studied Lappet-faced vultures, Aegypius tracheliotos in northern Namibia to discover how this face flushing ability is used. The team placed food at spots where vultures are known to gather at sunrise and monitored the wild birds’ interactions.

The team found that adults with flushed heads won the majority of social interactions against adults with pale heads and juveniles. However, adults with pale heads were not successful against juveniles.

The team also discovered that a previously unnoticed blue colouration also has an impact on the outcome of interactions. Adults with blue throats won the majority of their interactions with pale or red throated individuals.

“Our study has shown colouration correlates with the outcome of interactions in gatherings of lappet-faced vultures,” concluded Bamford. “Previously interaction was thought to depend on aggressive behavior, but face flushing status plays an important part in the initiation of, and response to, interaction from other vultures.” source

Keep the lights down low and hang feeders if you want the local birds to sleep in.

“In comparison to chemical and noise pollution, light pollution is more subtle, and its effects have perhaps not received the attention they deserve,” said Bart Kempenaers of the Max Planck Institute for Ornithology in Germany. “Our findings show clearly that light pollution influences the timing of breeding behavior, with unknown consequences for bird populations.”

The researchers investigated the effects of artificial night lighting on dawn song in five common forest-breeding songbirds. In four of those five species, males near street lights started singing significantly earlier in the morning than did males in other parts of the forest.

Further study of the effects of that behavioral shift on blue tits based on comparison of their reproductive behavior with and without street lights over a 7-year period showed real consequences. Females near street lights laid their eggs on average a day and half earlier. And males near lights at the forest’s edges were more successful in attracting “extra-pair mates,” meaning that they more often sired offspring with females other than their primary social partners.

That might sound like a bonus for those males, but Kempenaers said that doesn’t mean it’s good for the species, and it might not even be good for the males in question. read more

Feeding wild garden birds during the breeding season may delay the start of the dawn chorus sung by some species, say researchers.
Their study claims to have found a link between supplementary feeding and the observed changes in songbird behaviour.
The scientists made the discovery studying populations of great tits living in the suburbs of Oslo, Norway.
Birds with access to feeders delayed their song by up to 20 minutes, often beginning only after the sun had risen. Feeding garden birds such as tits delays dawn chorus

More information:

Wild bird feeding delays start of dawn singing in the great tit

Artificial Night Lighting Affects Dawn Song, Extra-Pair Siring Success, and Lay Date in Songbirds

Some birds can see magnetic fields like we see colors. Those with sharp vision see the field clearly, those with impaired vision have trouble same as we might reading small print in our later years.

Some birds can sense the Earth’s magnetic field and orientate themselves with the ease of a compass needle. This ability is a massive boon for migrating birds, keeping frequent flyers on the straight and narrow. But this incredible sense is closely tied to a more mundane one – vision. Thanks to special molecules in their retinas, birds like the European robins can literally see magnetic fields. The fields appear as patterns of light and shade, or even colour, superimposed onto what they normally see.
Katrin Stapput from Goethe University has shown that this ‘magnetoreception’ ability depends on a clear image from the right eye. If the eye is covered by a translucent frosted goggle, the birds become disorientated; if the left eye is covered, they can navigate just fine. So the robin’s vision acts as a gate for its magnetic sense. Darkness (or even murkiness) keeps the gate shut, but light opens it, allowing the internal compass to work. Read more Robins can literally see magnetic fields, but only if their vision is sharp

More information:
Magnetoreception of Directional Information in Birds Requires Nondegraded Vision (paper $)