Dear Dhanashree Paranjpe ,

Yes. It is possible. Karp et al. have published a study entitled "Molecular diagnosis of bird-mediated pest consumption in tropical farmland " in Springerplus. 2014; 3: 630.

Published online 2014 Oct 24. doi: 10.1186/2193-1801-3-630 describing a molecular method by which they demonstrate potential for pairing molecular methods with ecological analyses to yield novel insights into species interactions:

Springerplus. 2014; 3: 630.

Published online 2014 Oct 24. doi:  10.1186/2193-1801-3-630

PMCID: PMC4216319

Molecular diagnosis of bird-mediated pest consumption in tropical farmland

Daniel S Karp, Seth Judson, Gretchen C Daily, and Elizabeth A Hadly

Author information ► Article notes ► Copyright and License information ►

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Abstract

Biodiversity loss will likely have surprising and dramatic consequences for human wellbeing. Identifying species that benefit society represents a critical first step towards predicting the consequences of biodiversity loss. Though natural predators prevent billions of dollars in agricultural pest damage annually, characterizing which predators consume pests has proven challenging. Emerging molecular techniques may illuminate these interactions. In the countryside of Costa Rica, we identified avian predators of coffee’s most damaging insect pest, the coffee berry borer beetle (Coleoptera:Scolytidae Hypothenemus hampeii), by assaying 1430 fecal samples of 108 bird species for borer DNA. While feeding trials confirmed the efficacy of our approach, detection rates were low. Nevertheless, we identified six species that consume the borer. These species had narrow diet breadths, thin bills, and short wings; traits shared with borer predators in other systems. Borer predators were not threatened; therefore, safeguarding pest control necessitates managing species beyond those at risk of regional extinction by maintaining populations in farmland habitats. Generally, our results demonstrate potential for pairing molecular methods with ecological analyses to yield novel insights into species interactions.

To view the full publication, please use the following link:

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4216319/

Hoping this will be helpful,

Rafik

Thank you Rafik for the info and reference!

I know roughly what is available for the birds to eat in a specific area. However, the birds are omnivores--they can eat grains, fruits, tender leaves and sprouts, insects, sometimes even lizards and small snakes. So I want to know what they are actually consuming in a specific geographic area and does the diet change according to the season. If I cannot do gut analysis, can microscopic examination give me enough data to infer their diet composition or molecular identification is absolutely necessary?

Dear Dhanashree Paranjpe,

You still need molecular identification.

Rafik

Hi Dhanu, I found this one.

Carlisle et al (2006) Relative efficiency of fecal versus regurgitated samples

for assessing diet and the deleterious effects of a tartar

emetic on migratory birds. Journal of Field Ornithology 77 (2): 126-135.

Cheers,

Rodrigo

Poulin et al. have determined the insect orders (maybe families) in the faeces of swallows to search for the effect of spraying against moscitos in foraging areas. They were able to show a change of diet based on the consumed insect orders.

Poulin, Brigitte, Gaetan Lefebvre, and Leire Paz. "Red flag for green spray: adverse trophic effects of Bti on breeding birds." Journal of Applied Ecology 47.4 (2010): 884-889.

Hi Dhanu,

I work with molluscivorous birds for which diet recontruction through fecal analysis has been well developed. We have written two methodological papers on this that might be a source of inspiration for you (of course realizing that fecal analysis for your frugivorous birds is a different ball game)!

Dekinga & Piersma. Reconstructing diet composition on the basis of faeces in a mollusc-eating wader, the knot Calidris canutus. Bird Study 40, 144-156 (1993).

Onrust et al., Red knot diet reconstruction revisited: context dependence revealed by experiments at Banc d’Arguin, Mauritania. Bird Study 60, 298-307 (2013).

hope this helps!

Jan

Thank you Dr. Jan!

Can you please send me those papers? I am not able to get the full text on internet.

Dhanu 

sure, here they come!

Hello Dhanu,

I used to work with Sofia Rozenfeld, who is an expert in diet of geese (herbivorous). She has published a photo guide on cuticles of epidermal cells of vegetation, found undigested in faeces. The book is in Russian, but I can get you in touch with the author (she speaks good English)

Dear Dhanashree Paranjpe:

Yes, it is possible using more rustic methods and not just with molecular data, which I believe may be very costly. Nevertheless, I think everything depends on the scope of your study, the taxonomical detail that you will wish for your identifications and your budget.

You will find the literature plagued of examples of studies similar to the one you described and I am sure you will not have any trouble retrieving literature on this topic.

In my experience I have seen several colleagues conducting similar analyses and from what I remember possibly using regurgitation analyses besides faces can give you the best results; since some items will be possibly not identifiable after passing the whole digestive tract of the bird. Insects usually, will be identifiable to order and seeds possibly to species depending on several factors. Most importantly you will need to establish you own reference collection of seeds from the region, so you can identify whatever you will see under the stereoscope coming from your samples. This will apply to other items of the diet such as the elegant example that JK gave for the geese in the previous answer.

Hope this helps and gives you some more ideas for your study.

All the best,

Juan

Hello mam,

Within the old morphology based methods, pellet analysis is the most commonly used. As said above, you need a reference collection ready so as to identify the prey items readily. We had done a small qualitative study on spotted owlets in the same theme (https://www.researchgate.net/publication/282567380_Diet_of_the_Spotted_Owlet_Athene_brama_in_an_urban_landscape) . http://www.threatenedtaxa.in/index.php/JoTT/article/view/388/628 can also be of use.

There are loads of good quality papers far superior than ours especially on raptor diet (for eg. http://digital.csic.es/bitstream/10261/46664/1/2010.3.pdf). You can also get some of the references from the literature cited section in any of these papers. 

Further, people have also compared the dietary composition of birds to the relative abundance of prey in the given area. There are however some drawbacks in these methods such as prey items with soft parts are completely digested and nothing is represented in pellets, whereas those with undigestable keratinised parts are over-represented.

Article Diet of the Spotted Owlet Athene brama in an urban landscape

Julia, it would be wonderful to talk to Sofia Rozenfeld. A photo guide of what I should expect in feces will be extremely useful!

Thank you all for your valuable suggestions and expert opinion! I have two major constraints:

1. I would like to go for molecular analysis but do not have sufficient funds.

2. I cannot use regurgitation analyses.

That restricts my choice to microscopic analyses using reference collection of seeds/ fruits/ prey base in my study area.

Dear Dhanashree Paranjpe:

I did not clarify that with 'regurgitation' I meant a methodology to induce or force regurgitation in passerines using a small tube passed through their esophagus and an isotonic saline solution, which is a very simple methodology to implement in the field. In fact when you use this method usually you induce defecation too.

CheerS,

Juan

Thank you Juan for the suggestion!

I will be working with Indian Peafowl which is a BIG bird and I will need special permissions even to use simple techniques with the bird. Hence, I will have to do with fecal sample analyses for now. However, I will keep in mind the technique you suggested so that I might be able to use it in future.

Oh yes! that's pretty big for the technique I mentioned. I guess might be possible to do it, but handling the bird must be a real challenge. Being like that feces is possibly your best choice.

RegardS