Dear Hans, Well, that's exactly my point. That's why I had to mention twice that a question like this has to be very specific for a group of birds or particular species. :)
And, I don't know much about nidification of indian birds either despite of the fact that I get to see them everyday. :| Yes, Climate was a wrong choice of word. But I was probably thinking over a longer time and behaviour specific evolution to which the question sounded more related. I wanted to refer to the fact that even if there are changes in weather these birds wouldn't change their habitats or nesting habits by great extents over a short period. Perhaps, for the environmental factors that affect nest building, growth & development of chicks, molting in juveniles and young birds. Eg. Photoperiod Coming to the nests, I completely agree with you that most birds that nest in bare big trees are big enough, especially raptors to defend their nests. The nests themselves are so big that they can use all the extra space that bare trees offer. Also, yes.. they use twigs and sticks for their nests. But, smaller birds that may choose such sites as I said have amazingly well camouflaged nests. Recent ones I observed were Thick-billed Flowerpecker nesting on a bare tree with very few completely dry leaves just drooping. But, it nests in such a beautiful fashion, it takes one time to know it's a nest and not another dry leaf. Another was the Common Woodshrike which was seen nesting on a completely bare tree. It builds nest in shallow forks of horizontal branches and is very well camouflaged. Weavers are a completely different story. By leaf litter I did not mean just leaves, however they are used by most Laughingthrushes for nesting for example (But as you said leafy surroundings). Small pieces of leaves, stalks, shafts, cotton (We get lots of silk cotton from silk cotton trees (deciduous) in this season here). After all, birds are superbly resourceful and can work well with abundantly available things. The need of better view, (for predators) of nest may not be certainly bothering big birds like Golden Eagle, but for smaller birds it may be of little greater importance especially when they wouldn't want to reveal their nests. I've observed how hesitant they are to enter, if you're near their nests. And in addition things I said earlier about food availability. Of course, what I said was in a general manner & conjectural, for the imprecise question, but a very good one. There obviously is more to nesting behaviour than it meets the eye and only can be commented on with accurate studies and observations. Although, I know nothing; I believe, it must be one of the least studied aspects of Ornithology no matter how well documented it must be but poorly reasoned. Thanks for your great inputs. I'd love to read more :) Best, Saurabh On Thu, May 24, 2012 at 3:52 AM, Hans Peeters <[email protected]> wrote: > Dear Saurabh, > > I must confess that I'm not at all familiar with the nidification of a > great many Indian birds; for example, I know nothing about the nests of > fulvettas, shrike-babblers, and minlas. In the areas of the world that I > know well, the vast majority of birds place their nests in well-hidden > situations and begin nesting when the weather (and not the climate, which > is a given) is optimal for raising young. The main factor, I believe, is > the abundance of food for the offspring. Our common accipiter here in > California, the Cooper's Hawk, builds its well-hidden nest in March and > April and fledges its young in June, when there is a maximum number of > inexperienced, newly fledged songbirds available for its own clumsy > youngsters that are just learning to hunt. > > Birds that breed in extremely exposed situations, such as leafless trees, > almost always seem to be large enough to defend eggs or young against any > potential predator, and they seem to see no need to hide their nests. > Almost always, these are large birds such as herons, storks, big raptors, > etc. (in our last trip to India, in Feb/Mar, we noticed all the black kite > nests going into perfectly bare trees, and even a crow nest here and > there). At a minimum, there is at all times normally one adult at the nest > once it holds eggs or small young; once the young are well grown, both the > adults will leave the nest alone and forage. The only smallish, relatively > helpless birds I know that build in exposed situations are some of the > caprimulgids (for example, the potoos of South America), which rely on the > camouflage of the adult and the young, and the fairy tern of Pacific > islands which lays its egg directly onto a limb, benefiting from the > absence of predators. > > Other than that, I cannot think of any small birds that cleverly disguise > their nests in bare trees, and I would be really interested in learning of > species that do so. I suppose you might mention the spotted creeper, whose > nest, however, sort of melts with the bark of the tree. I have seen the > nest of drongos and the nests of some other passerines which seem to be > fairly obvious hanging from or saddling a limb, but the ones I've seen have > been in leafy trees, not in bare ones. Weavers build very conspicuous > nests, sometimes in bare trees, but the nests themselves appear to be > virtually impenetrable except to certain snakes. Plus, they nest > colonially -- there's safety in numbers. Lichen-covered hummingbird nests, > which for all the world look like a knot on the limb on which they're > built, nevertheless are usually placed in leafy locations. > > Note that the nests of the larger birds I mention earlier are robust > affairs, made of sticks, sometimes even very large ones. Leaf litter is > rare building material, and when used, it typically will be by a bird > nesting in leafy surroundings. > > I don't believe that birds need a better view of their nest site nor any > help in spotting predators. Golden eagles in California, for example, > whose nests may be either exposed or well hidden in the crowns of oaks, > know precisely where their nest is, fear no predators, and often approach > the nest flying under the canopy, where they cannot see their objective. > > All this from Rajesh's innocent but perfectly good question why birds nest > in bare trees. > > Best regards, > Hans > > > On Tue, May 22, 2012 at 8:07 AM, Saurabh Sawant > <[email protected]>wrote: > >> Quoting my reply to this question, from facebook, as I'd be happy to >> learn more on this: >> >> "Nesting activity is influenced by a number of factors. And considering >> the scope of this question; which only appears to be narrow at first can be >> really vast, it can be addressed better if it is specified for particular >> group of birds. Because, different species have different preferences and >> habits though the habitat could be the same but for different reasons & >> microhabitats. >> Some of the major, apparent factors that influence the nest site choice >> could be Climate, Predators, Availability of Food & perhaps, Availability >> of nesting material. There could be numerous smaller and subtle factors >> which play a big role in choosing nesting site for birds create a highly >> localized environment to their preferences. >> Firstly it avoids a lot of efforts and competition for not so abundant >> nesting sites. So it's better to adapt than to compete. Most of all these >> birds which make their nests in the open on branches of deciduous trees are >> extremely well camouflaged and cryptic. And believe me, are extremely hard >> to locate. So, whether in the open or not, they are well hidden. They must >> be helping the birds probably to have a better view of their nest site and >> predators lurking around. It may be associated with direct sunlight in the >> morning, vegetation cover above or brood temperature. Other animals may not >> be finding such sites suitable for shelter which would avoid attracting >> predators. The twigs, branches, leaf litter from deciduous trees must be a >> good source of nesting material and also superb habitat / shelter for many >> animals including most of bird's prey base. Deciduous trees will have new >> leafbuds, young leaves, flowers, fruits as soon as the season passes or >> comes near its end. Which may be a great food source for birds or other >> animals which are part of bird's diet. etc.. These are a few in general and >> there could be many such factors. >> Questions such as these can be addressed effectively if pertained to >> specific group of birds or species. But of course, only after a lot of >> observation. :)" >> >> Regards, >> Saurabh >> >> On Mon, May 21, 2012 at 3:02 PM, Rajesh Sachdev <[email protected]>wrote: >> >>> It is observed that the nesting birds , camoufledgly build or regenerate >>> their nest every season. It is also understood that they try every step >>> hard to hide their nest with local vegetation or foliage. Than, why many >>> birds build their nest on deciduous trees, which are bare/leafless in the >>> season of summer or before spring. And that is the time when most of >>> resident birds are in breeding plumage and busy with their nesting activity! >>> >>> -- >>> Regards >>> Rajesh Sachdev >>> http://project-matheran.webs.com >>> https://www.facebook.com/leopardguy >>> >>> >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "delhibirdpix" group. >>> To post to this group, send email to [email protected]. >>> To unsubscribe from this group, send email to >>> [email protected]. >>> For more options, visit this group at >>> http://groups.google.com/group/delhibirdpix?hl=en. >>> >> >> >> >> -- >> Regards, >> Saurabh Sawant >> _ >> "The foot feels the foot when it feels the ground." >> >> http://www.facebook.com/saurabh.sawant >> >> http://www.flickr.com/photos/40451253@N04/ >> >> -- >> You received this message because you are subscribed to the Google Groups >> "delhibirdpix" group. >> To post to this group, send email to [email protected]. >> To unsubscribe from this group, send email to >> [email protected]. >> For more options, visit this group at >> http://groups.google.com/group/delhibirdpix?hl=en. >> > > > > -- > Hans Peeters > 1050 Kilkare Road > Sunol, CA 94586 > USA > 925-862-2102 > http://peeters.homestead.com > http://www.ucpress.edu/books/pages/10558.php > http://www.ucpress.edu/books/pages/9944.php > > -- Regards, Saurabh Sawant _ "The foot feels the foot when it feels the ground." http://www.facebook.com/saurabh.sawant http://www.flickr.com/photos/40451253@N04/
