Hot answers tagged

19

The question is all about nomenclature (and a little bit of semantics). One can call reptiles whatever (s)he wants. The question is what do we define as being a reptile? And the answer is that there are two possible definitions, a common "bad" definition (Definition 1) and a phylogenetic-based "good" definition (definition 2). I think your confusion comes ...


18

Yes, mantises hunt cicadas... Mantis eating cicada. Source: Dreamstime. ...and yes, orioles hunt cicadas too... Oriole eating cicada. Source: Bird Ecology Study Group. .., and what may be more relevant to your idiom: orioles prey on mantises. Oriole eating mantis. Source: Sustainable Adventure.


17

Birds have a body part known as the nicitating membrane otherwise known as the "third eyelid". This part has become vestigial in humans, where it remains as the plica semilunaris. This image of a masked lapwing clearly shows its nicitating membrane in action, where it covers the eye in a horizontal motion. This is analogous to blinking in humans, and the ...


16

I just weighed a pigeon tail feather (~10 cm) long. The mass was 0.05 g. Although all tail feathers are not equal in length (and all pigeons are not equal in size), this is probably a good approximation. Measuring the drag coefficient is going to be very challenging, because it will vary with the orientation of the oncoming airflow. A feather falling with ...


16

Short answer Birds emit infrared. Background Objects with a temperature higher than the background emit detectable infrared (IR). Endothermic (warmblooded) animals keep their body temperatures at around 37oC and given the relatively cool temperatures at the earth's surface, endotherms generally emit more IR than the background. Endothermic animals include ...


11

We really don't know - we can't really ask the chicken. At least, it's unlikely it's as painful as it can be with humans. The reason human birth is (or can be) very painful is that the human baby's head has to fit through the woman's pelvis. Since splitting from chimpanzees, human heads have gotten bigger, while the pelvis has gotten more narrow due to ...


11

This phenomenon is called tonic immobility. And those speculations you've mentioned are wrong: they do get back on their feet, only remain in that state for a prolonged time, which depends on the distance and eye contact with whoever laid the chicken on its back, as stated here. From this experiment, it can be concluded, that this behavior in which the ...


5

Based on the location and picture I believe this a Spotted Sandpiper (Actitis macularis) chick. Once they hatch, they are out of the nest, the one you are holding looks fairly small still, must have hatched recently. You can find more information about them here.


4

I don't know about the specific cues that American robins use for migration. This species is also both a short range (e.g. between states or to lower altitudes) and long range migrant (e.g. Florida & Mexico), so the cues that they use can probably differ between overwintering populations. There are also year-round populations of robins in the US, but ...


4

Richard Dawkins discusses this in his book The Greatest Show on Earth: The Evidence for Evolution. The birds, in the aforementioned example Starlings, 'know' which direction to fly and where to be by obeying simple local rules concerning the distance and spacing of other members of the flock in their immediate vicinity, without any global knowledge of the ...


4

First of all, dinosaurs did not evolve to birds. A better way of saying it is that modern birds evolved from a particular type of dinosaur. That, however, is not the same as the blanket statement "dinosaurs evolved to birds". The latter implies that dinosaurs somehow morphed into birds and stopped being dinosaurs. What actually happens is that a species ...


4

Hummingbirds were not created, they evolved. Ancestors of a modern species need not be that morphologically different from their progeny, even over a time span of millions of years. And organism will fill a niche based on its fitness to survive in the niche. If there are strong selective pressures in the environment to maintain the traits that we see ...


3

Welcome to Biology.SE. Did you say warm-blooded? The term warm-blood is very unclear. The correct terms are endo-, exo-, poikilo- and homeo- therm. In short… Source of heat endo = inside exo = outside Variation in inside temperature Poikilo = varies homeo = does not vary Any combination of these two axes exist. For example: If the ...


3

From this paper about black-headed gulls responding to a hedgehog: The gull might peck the intruder, or strike it with its feet. Pecks were mostly directed at the hedgehog's head and might be delivered after a horizontal approach with the wings partly lifted. Although not directed at the eyes specifically, they observed the birds directing attacks ...


3

The order of settling depends on the resource availability in different patches (in your case the difference between high and low quality habitat), but generally speaking, the pattern you observe conforms to the ideal free distribution. The key factor in the ideal free distribution is that habitat patches are filled according to the current resource ...


3

Following your answer to my comment, I deduced the “yellow” color to be more brownish as there is not big bird with really bright yellow color (like the golden oriole). With these parameters I search as well in the ornitho.ch database (all observations given by ornithologist professionals and amateurs) : there was no observation of vulture or eagle in that ...


2

I'm not a specialist in this area, but I would guess that the length of day-light periods compared to night time could be a good trigger. This is quite independent of the weather, is quite constant (even though length of days is known to have changed through over the millions of years past since the formation of earth).


2

The technology is not there (yet) for deployments on 10 gram birds. The limits for GPS technology are around the 50 g range, for birds. Also bear in mind that the smallest loggers are generally not capable of transmitting, so you would need to recapture the animals to retrieve your data. As your question implies, there is a strong trade-off between device ...


2

Dinosaurs is a very broad term which includes both the ancestors of birds as well as modern reptiles. But that analogy stretches as far to say that a bird is a modern dinosaur and a reptile is a modern dinosaur but a bird is not a reptile. Both of their ancestors lived during the cretaceous period and tend to get lumped together. Another analogy would be ...


2

So, we typically think about migrating birds as living somewhere (North) and then traveling South for the winter. This way of thinking is actually not accurate according to a number of ornithologists, including many I used to work with/for. Thy suggest that the birds live in the South and migrate North to breed and to avoid overcrowding of Southern locales. ...


2

Birds find their niches based on many reasons. Their choice is based on primarily resource availability, predation risk, and competition. Keep in mind there are variations among species, most birds like to forage for food at a hight safe enough to avoid ground predation, at the same time to be able to see and find food without much competition. Therefore ...


1

Birds (crows inclusive) have better heat conservation adaptations as compared to humans. Some of these are (but not limited to): -Hollow tubes in feathers which provide insulation reducing heat loss. -Reduction of appendage length especially in species that dwell in cold regions. So conditions we perceive as cold are relatively warm for birds. My ...


1

There are a variety of physiological, anatomical and behavioral adaptations that keep birds warm in winter. For starters, birds are endothermic ("warm-blooded"), similar to mammals. You suggested that the coats humans wear are superior to feathers as insulation. Yet some of the finest coats and sleeping bags were long filled with feathers (e.g. goose down). ...


1

It would help knowing your location, though that would still leave a lot of guesswork. For example, did the birds KNOW it was going to be a warm winter? If a bird sensed a warm winter and chose to stay put, rather than migrate, only to be caught by a sudden freeze, the results could obviously be disastrous. A severe drought combined with dire weather ...


1

I found the same in this book, published just over 100 years ago. The book appears to be the result of some pretty rigorous study, so I expect it is a reliable source. On page 294, it refers to the gizzard as an involuntary sphincter, and again on page 302 it refers to the grinding of food in poultry as involuntary. In fact it says that because poultry ...


1

Involuntary. The gizzard, like our stomachs, works unconciously. However, chickens do choose to peck up stones to help along the process, whether that is by instinct or otherwise. (I raised chickens a long time but a proper reference is below) This book on commercial poultry raising says involuntary


1

I will assume that you are talking about Mallards, although other wildfowl are likely to exhibit similar behaviors. Mallards aren't actually solitary during the summer, instead they form breeding pairs. They form groups (sords) in the winter to migrate and for protection while moulting. ...


1

I have found these papers: http://www.sciencedirect.com/science/article/pii/S0169534713002322 http://www.sciencedirect.com/science/article/pii/S0040580912001360 http://www.ncbi.nlm.nih.gov/pubmed/19416834 http://www.ncbi.nlm.nih.gov/pubmed/21930936 The last two argue that larger groups have better "problem solving" capability, and this is a clear ...


1

Birds, like amphibians, have a third eyelid (the nicitating membrane) that helps them keeps their eyes moistened and allows them to better visualize at high speeds (or, for amphibians, underwater). The glands in birds' eyes allow them to secrete a fluid that is more resistant to evaporation than tears. The membrane also acts as a 'windshield wiper,' with ...


1

Thank you for these answers. My robin sightings decreased over the first few weeks since I wrote this, however they're back in full force now. This made me curious enough to do further research, and I happened upon two fact sheets about American Robins, whose scientific name is Turdis Migratorius, meaning Migrating Thrush. I've extrapolated data from a ...



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