Ah, yes. We definitely missed out on an obvious one there. And you read me correctly. This discussion was very insightful. :)
Regards, Saurabh On Thu, Jun 7, 2012 at 2:58 AM, Hans Peeters <[email protected]> wrote: > Dear Saurabh, > > Kiran Srivastava mentioned to me that he had seen a treeswift nest some > time ago and how very difficult it was to find it again each time he > visited it even though it was right out in the open on a bare tree branch > at some height. I don't know why you and I hadn't thought of this species > -- it's well known for its peculiar nest, a tiny minimal cup made of bark > bits and small feathers glued with saliva to a branch. This type of nest > nicely supports the recent DNA work that demonstrates the long-held belief > that treeswifts are closely related to true swifts (Apodidae), which build > a very similar nest albeit in more sheltered situations. Anyway, the > treeswift adds one more example to your list of well-camouflaged nests of > small birds built in bare trees. Still, a very short list, and these > species are truly exceptions among smallish birds in nest placement. It's > also interesting that the smallest herons, instead of building their nests > out in the open as is typical for most members of the family, nest in dense > bushes and trees. And Cattle egrets, being sort of mid-sized, will nest > colonially in bare trees but often hide their nests in leafy trees when > they are breeding as single couples. > > I'm not sure I am reading you correctly, but I believe you mean to say > that birds *do* change their nesting habits because of changes in > weather, and that is certainly true. The current global warming is > producing major changes both in North America and in Europe, with many > birds beginning to breed much earlier in the year than they used to. For > example, in the Rocky Mountains of the U.S., American Robins (actually a > large thrush) arrive at their high-altitude breeding grounds two weeks > earlier from spring migration than they did a few years ago, and go on to > breed with the result that there is insufficient food for the young. There > are many examples of range expansion and even of movement into new habitats > because of weather changes. Birds are very labile when it comes to > acceptable parameters for breeding; the photoperiod is just a rough > indicator as shown by a temporary display in autumn of breeding behavior by > North American birds that does not result in actual breeding because of the > absence of certain stimuli. It's all very interesting! > > Best regards, > Hans > > > > > On Mon, May 28, 2012 at 12:15 AM, Saurabh Sawant <[email protected] > > wrote: > >> 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/ >> > > > > -- > 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/
