# Birdathon vs Delta

The clearest difference is rating: Birdathon at 4.7 against Delta's 3.1. Birdathon also leads on review sentiment (100% vs 67%) and monetization model (free vs freemium). Delta's advantage is update cadence (monthly vs every 4 months) and device support (4 vs 2). On price, ratings volume, ads and in-app purchases there is nothing between them.

Both are free to download. Birdathon sells 4 one-off in-app purchases and Delta sells 3 one-off in-app purchases. Whichever you choose, the download price is not the number that matters.

Birdathon holds the better App Store score, 4.7 against 3.1. Both are backed by a comparable volume of ratings — 15 and 7 respectively. Written reviews point the same way: 100% of Birdathon's written reviews are positive against 67% of Delta's.

Birdathon ships an update every 4 months, Delta monthly. The most recent releases landed on September 19, 2026 and August 19, 2026 respectively.

## The numbers

| Metric | Birdathon | Delta |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.7 (15 ratings)](https://appshunter.io/ios/app/birdathon/id1211977440/reviews)** | [3.1 (7 ratings)](https://appshunter.io/ios/app/delta-algorithms/id1436506800/reviews) |
| Number of ratings | **15** | 7 |
| Positive reviews | **100.0% of reviews** | 66.7% of reviews |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Every 4 months | **Monthly** |
| Monetization | **Free** | Freemium |
| Size | 192 MB | 5 MB |
| Requires iOS | 16.1 | **13.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod, Mac** |
| Age rating | 4+ | 4+ |
| Developer | [Barry Langdon-Lassagne](https://appshunter.io/developer/730758814) | [Groupe MINASTE](https://appshunter.io/developer/1378426984) |

## What reviewers say

### Birdathon

[App page](https://appshunter.io/ios/app/birdathon/id1211977440)

This app helps birdwatchers create and organize detailed checklists of their observations. It automatically records time and location, allowing for easy editing and customization. Users can visualize their sightings on maps, add field notes, and export data for sharing or further analysis.

**Highlights:** Observation-centric checklists, Automatic time and location recording, Customizable maps with boundary overlays, Field notes for additional observations, Multiple checklist sorting options, Data export to CSV and other formats, Create checklist templates

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Good Tip | $0.99 | one-time |
| Great Tip | $1.99 | one-time |
| Amazing Tip | $2.99 | one-time |
| Incredible Tip | $4.99 | one-time |


### Delta

[App page](https://appshunter.io/ios/app/delta-algorithms/id1436506800)

This app helps users solve math problems by creating and executing algorithms. It offers tools for homework checking, test preparation, and creating custom quizzes. Users can save, share, and download algorithms via the cloud.

**Highlights:** Create algorithms with natural language, Execute algorithms to solve math problems, Create and download custom quizzes, Save and share algorithms, Cloud synchronization for algorithms

**Features:** Vision Pro support

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Donation 1 | $0.99 | one-time |
| Donation 2 | $2.99 | one-time |
| Donation 3 | $4.99 | one-time |


## Frequently asked questions

### Is Birdathon free?

Birdathon is free to download, with in-app purchases available.

### Is Delta free?

Delta is free to download, with in-app purchases available.

### Which has better reviews, Birdathon or Delta?

Birdathon is rated higher. Birdathon averages 4.7 out of 5 from 15 ratings, while Delta averages 3.1 from 7 ratings.

### Do Birdathon or Delta have ads?

Neither Birdathon nor Delta shows ads.

### Which is updated more often, Birdathon or Delta?

Birdathon ships an update every 4 months, and Delta monthly. Most recently, Birdathon was updated on September 19, 2026 and Delta on August 19, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*