10 Indian BIRDS Vol. 16 No. 1 (Publ. 13 July 2020)
Guidelines for conducting research on the nesting biology 
of Indian birds
Sahas Barve, T. R. Shankar Raman, Aparajita Datta & Girish Jathar
Barve, S., Raman, T. R. S., Datta, A., & Jathar, G., 2020. Draft guidelines for conducting research on the nesting biology of Indian birds. Indian BIRDS 16 (1): 10–11.
Sahas Barve, Smithsonian National Museum of Natural History, 10th Street and Constitution Avenue NW, Washington, D.C. 20560.  
E-mail: sahasbarve@gmail.com. [Corresponding author.]
T. R. Shankar Raman, Nature Conservation Foundation, 1311, ‘Amritha’, 12th A Main, Vijayanagar 1st Stage, Mysore 570017, Karnataka, India.
Aparajita Datta, Nature Conservation Foundation, 1311, ‘Amritha’, 12th A Main, Vijayanagar 1st Stage, Mysore 570017, Karnataka, India.
Girish Jathar, Bombay Natural History Society, Hornbill House, Dr Salim Ali Chowk, Shaheed Bhagat Singh Road, Mumbai 400001, Maharashtra, India.
Manuscript received on 03 February 2020.
This document presents suggested guidelines for studying tree or branch, at a considerable distance away from the nest, the nesting biology of Indian birds for professional or can act as a reminder for you. Natural markers, such as a heap amateur bird researchers. They have been modified from, of stones pointing in the direction, may also be used. Draw a 
and adapted for, the Indian context from similar resources diagram detailing the tree or plant species the nest is in, the 
developed by the British Trust for Ornithology (BTO 2019) and height of the nest, and approximate location on the tree. Good 
the Cornell Lab of Ornithology (CLO 2019). This first version of notes on nest location also include details of nest such as branch 
these guidelines is being published here accompanying the Barve orientation, any specific marks (e.g., the nest is c.2 m from the 
et al. (2020) paper in Indian BIRDS to solicit comments from main stem, on a dead branch pointing north, c.6 m off the ground 
birdwatchers, researchers, conservationists, and others interested in a Mangifera indica tree). In essence, the notes on the location 
in bird research and conservation. We especially encourage of the nest should be detailed enough to enable you, or anyone 
scientists that study raptors, wetland birds, ground-nesting birds on your research team, to easily find the nest without walking 
and colony-nesting birds to contribute specifics related to those around the nest location for too long.
taxa. Please send your comments to the Editor, Indian BIRDS 
(editor.indianbirds@gmail.com) within three months from the 
publication of this version. Number of nest visits
The number of nest visits you need to make depends on the 
goal of the study but this should be planned well to minimize 
Guiding principle impact (Götmark 1992; Mayer-Cross et al. 1997). Some studies 
Minimizing disturbance caused by the observer at nests is may require frequent visits at a certain nesting stage of interest; 
paramount. The observer should always put the safety and e.g., to ascertain fledging dates accurately. If the aim is to simply 
welfare of the bird(s) before the success of their research. Utmost monitor the nest to follow its progress, then it should not be 
care should be taken to make sure that research methods do visited more than once every three to four days to minimize 
not jeopardize the nest(s) or the birds in any way. impact. Before visiting a nest, make sure you are well prepared 
with all the necessary equipment (e.g., data sheet, clipboard, 
research equipment, cameras, stopwatch, etc.), and that it is 
Recording the location of the nest easily accessible so as to spend as little time as possible once 
You may become aware of a nest when you see a bird with you reach the nest site, or while you set up your observation 
nesting material in its beak, or one carrying food in its beak post. Elevated platforms work well for nests high up in the trees. 
(birds rarely fly around with food in their beaks except when Concealing yourself in a portable hide, or wearing the same, or 
they are feeding nestlings. An obvious exception is raptors, or similar clothing during every visit, minimizes the stress you cause 
birds that are engaged in courtship feeding, or carrying food the nesting birds. Hole-nesting birds tend to have lower predation 
items that are too large to swallow whole). If you are going to rates than open nesting species. Yet, observations at the nest, 
search for the nest, it is highly recommended to first try and regardless of whether the species is hole-nesting or not, should 
learn the nesting habits of the species, to get a sense of where be done from at least 12–15 m away. 
you should look for the nest. Always be very careful when 
walking through habitats like dense undergrowth or grassland 
so that you do not disturb, step upon, or dislodge nests of other Appropriate time for visiting nests
birds. Optimal times for visiting nests vary according to the bird 
When you find a nest that you want to follow, make detailed species in question. As far as possible, do not visit nests early in 
notes on the location of the nest. Nests, especially open cups, the morning. Many passerines lay eggs in the morning and may 
are notoriously good at hiding in plain sight and re-finding a be disturbed while doing so. Most birds lay one egg every day 
nest can be surprisingly and annoyingly tricky. If possible, take a so if you are interested in knowing the final clutch size of the 
photograph or video of the nest’s location. Taking a GPS location nest, plan your next nest visit depending on how many eggs 
and flagging the nest with an artificial marker, e.g., a tape on a are in the nest already and how many eggs are typically laid 
barVe et al.: Nesting biology of Indian birds 11
by the species according to literature. For example, if you visit birds show very high fidelity to nest sites, especially where they 
the nest on 11 March and see one egg in it, and the species have successfully fledged young in previous nesting attempts, 
is known to lay five eggs on average, going to the nest on 17 and will reuse these sites multiple times. The dimensions of the 
March and finding five eggs will give you the first egg’s laying nest cavity entrance that is selected or made by the bird reduces 
date, and that of the last one (in this case 15 March), and the chances of a predator entering the cavity, or a larger, more 
the size of the final clutch. Parents also tend to feed nestlings dominant species, usurping the cavity. When studying hole nests, 
more actively in the morning since they have not been fed the entrance of the cavity should not be modified in any way. A 
since the previous evening. It is also not advisable to check flex-metal tape or bamboo strip can be used to measure the inner 
nests late in the evening when parents may be returning to dimensions of a nest. Nestlings should not be handled without 
the nest to brood the eggs, or the nestlings, for the night. It is the appropriate permits. Care should be taken to use appropriate 
a good practice to visit nests in the late morning or afternoon. methods and obtain training in their correct use. Although the 
Avoid nest visits for open-cup nesting species on rainy days number of times the nestlings are handled or measured will 
or when it is cold. Parents will often sit over nestlings to keep depend on the research question, getting the research methods 
them dry and warm but will flee on your arrival, leaving the approved by a research ethics committee can help ensure that 
nestlings exposed to the elements, or even to predation. Food, maximal information can be gathered with the least amount 
especially insects, may be harder to find on cold/rainy days, of handling. Many birds, especially large, group-living or colony 
and so nestlings may be more stressed during inclement nesting birds are known to mob predators. Mobbing may involve 
weather. For most birds, including ground-nesting birds, open- alarm calls and defecation, but may also include flying close to 
cup nesters, cavity nesters, and water birds nesting in colonies, and/or pecking predators. Researchers visiting the nests of such 
observe the nest(s) in question from far to make sure that a birds may elicit a similar behavioral response and should wear 
parent is not sitting on the nest, and only approach it when proper clothing (hard hats or helmets) to protect themselves 
the bird leaves on its own. Approaching the nest when the from injury.
nestlings are close to fledging, but not fully ready to fledge, can 
cause ‘forced-fledging’, or young leaving the nest prematurely, What to do when you find an abandoned nest
which significantly increases the risk of predation for the young. If you find a nest with eggs or nestlings and no parents, verify 
When young are close to fledging, observe from a safe distance that the nest is in fact abandoned. Birds may leave eggs 
to avoid premature fledging behaviour. Ground-nesting birds abandoned for several minutes or even hours, especially before 
are particularly vulnerable to predators, and hence nest visits incubation. Nestlings may also be left for several hours by their 
should be made when predators are least active. parents. Birds may be hesitant to return to the nest for several 
minutes or hours after your visit. Frequent visits to the nest may 
Avoiding revealing the location of the nest to also cause nest desertion, especially among birds breeding for 
predators the first time. 
Avoid leaving tracks that can lead predators to the nest (Ibáñez- 1. Do not assume the nest is abandoned just because you 
Álamo et al. 2012). Avoid trampling the vegetation around the don’t see the parent birds in the vicinity for several minutes 
nest, which may make the nest more visible. Nest predators are or even hours. 
everywhere. These include, avian predators such as members 
of the crow family (Corvidae), coucals (Centropus spp.), and 2. Do not touch the eggs or nestlings. This is most likely illegal 
raptors (Accipitridae) to name a few; mammalian predators such without the right permits. 
as mongooses (Herpestidae), civets (Viverridae), cats (Felidae), 
rodents such as rats (Muridae) and squirrels (Sciuridae), and 3. Do not try to raise nestlings on your own. Other than it being 
several species of snakes. Especially if visiting the nest often, illegal, wild birds are very difficult to take care of. Bring them 
avoid visiting it at the same time on each visit; do a ‘walk-by’ of to a local wildlife rehabilitator who may have the right permit 
the nest rather than approaching it in a straight line and retreating to temporarily house them and the knowledge of caring for 
on the same path. Choose a track that generally disturbs the them.
vegetation as little as possible. In general, keep nest visits to a 
minimum and do your best to ascertain that you are not being References
watched by a predator. When visiting nests that are in water or Barve S., Raman T. R. S., Jathar, G., & Datta, A., 2020. When and how to study nesting 
on an island, do not create a path of rocks, or a bridge that leads biology of Indian birds: research needs, ethical considerations, and best practices. 
to the nest, as it may make it easy for a land predator to get to Indian BIRDS 16 (01): 1–9.
the nest(s). BTO. 2019. British Trust for Ornithology.Website URL: https://www.bto.org/our-science/
projects/nrs/coc. [Accessed on 06 December 2019.]
CLO. 2019. Cornell Lab NestWatch protocols. Website URL: https://nestwatch.org/
Measurements of nests and nestlings wp-content/uploads/2014/07/NestWatch_manual_140715.pdf. [Accessed on 06 
Any physical measurements of nests (size, or nesting materials December 2019.]
used) should be done after the nestlings have fledged from the Götmark, F., 1992. The effects of investigator disturbance on nesting birds. Current 
nest. Removing nests for study requires appropriate permits. Ornithology 9: 63–104.
Ibáñez-Álamo, J. D., Sanllorente, O., & Soler, M., 2012. The impact of researcher 
Many birds, especially tropical species, nest multiple times in disturbance on nest predation rates: a meta-analysis. Ibis 154 (1): 5–14.
a year, and many species (e.g., drongos, Dicruridae) reuse old Mayer-Gross, H., Crick, H. Q. P., & Greenwood, J. J. D., 1997. The effect of observers 
nests, or nesting materials, so care should be taken when studying visiting the nests of passerines: an experimental study. Bird Study 44 (1): 
nests such that they are not harmed in any way. Hole-nesting 53–65.